rust inside brake calipers: use converter or remover?

[GDVink]

I'm rebuilding my brake calipers on a '97 Ford Explorer and have dissassembled everything and removed the old rubber seals. There's quite a bit of rust INSIDE the calipers, where they come in contact w/ brake fluid.

My question: is it better to use a) rust remover (phosphoric acid), b) rust converter (tannic acid and polymer or c) not worry about it?

By the way, the areas that hold the rubber seals for the pistons are not particularly rusty, the pistons are in very good shape, and the calipers didn't leak or stick before I started this project. So I'm not worried about the various grooves holding the rubber seals -- just about the remaining interior rust.

I hope this forum is an OK place to ask this question, but I'm assuming shop chemicals count as tools? (Also, I did a search and read the very informative, multi-response thread about different types of rust removers), https://www.garagejournal.com/forum/showthread.php?t=355329&highlight=rust+remover

Thanks for any opinions.

 

[anndel]

I would use sandpaper, scraper, pick, Roloc, etc. to remove the rust then spray with brake parts cleaner. If you're talking about large flakes and/or chunks of rust I would replace the caliper since the structural integrity of the caliper is diminished.

 

[fordkid88]

Brake fluid would just remove the paint. So if your gonna go that route I would convert and hope it doesn't cause sticking from out of whack tolerances. Or just use the old ones as cores and get new ones.

 

[d.mcfarland]

If I was that far into the repair I dam sure wouldn't be reusing the old ones if I knew they were badly pitted.

The new (reman) ones are probably $70 for both. I know everyone hates spending money on something they don't want, but the brakes are fairly important to me, not sure about you.

I'm sure a rebuild "could" work, but for how long and if they fail when will it be?

 

[American Locomotive]

A front caliper for that Explorer can be had for as low as $27.

IMO, it's not worth the effort to try and clean the rust up - especially if it's on the cylinder bores. Brake components are one of those things I really don't like to mess around with. The last thing I need is a bit of rust to cut a piston o-ring, or mechanical sanding to take the bore out of round.

 

[Flat-rate]

We used to sand blast them back in the day, before inexpensive rebuilds became available.

My 07 Honda had a binding caliper. Some how water got in past the dust boot and rusted the O-ring area. The brake fluid side was perfect. Called up the local parts store and had a rebuilt here faster than it would take to clean out the rust AND locate just a seal kit.

 

[Fedwrench]

We're talking a 1997 Explorer not a rare or exotic classic car that you can't get parts for. Be safe & buy new calipers.

 

[6PTsocket]

I'm rebuilding my brake calipers on a '97 Ford Explorer and have dissassembled everything and removed the old rubber seals. There's quite a bit of rust INSIDE the calipers, where they come in contact w/ brake fluid.

My question: is it better to use a) rust remover (phosphoric acid), b) rust converter (tannic acid and polymer or c) not worry about it?

By the way, the areas that hold the rubber seals for the pistons are not particularly rusty, the pistons are in very good shape, and the calipers didn't leak or stick before I started this project. So I'm not worried about the various grooves holding the rubber seals -- just about the remaining interior rust.

I hope this forum is an OK place to ask this question, but I'm assuming shop chemicals count as tools? (Also, I did a search and read the very informative, multi-response thread about different types of rust removers), https://www.garagejournal.com/forum/showthread.php?t=355329&highlight=rust+remover

Thanks for any opinions.

I salvaged a caliper like that with Evaporust. Acid converters remove rust but etch good metal as well. You want to end up with a smooth bore and not one coated with iron phosphate where there was rust and an etched surface where there was no rust. As a follow up I would use crocus cloth to polish the surface with minimal metal removal. After the rust is gone I would evaluate the bore to decide if I want to use it or trade it in for a refurb.

Sent from my SM-G900V using Tapatalk

 

[matt01073]

Reman calipers are probably the same price as seal kits, havent rebuilt a caliper in 30 years or so . They are way to cheap reman to mess with

 

[apollo11]

need pics to really answer the question correctly
they probably only need minor clean up but again w/o pics everyone is guessing including me

 

[smalltown]

GDVink I recently just finished rebuilding all 4 calipers on my Explorer Sport Trac.
I used the electrolysis method to clean them up. It worked great. My brakes are working fine, and just passed a state inspection.

P.S. time wasn't an issue with mine. I did one front and one rear at a time so I could compare with one I had not changed.

 

[AJ.]

Electrolysis is the go, here is a set I did a while ago for my Landcruiser.

https://pixxxels.org/

https://postimage.org/

https://postimage.org/

https://postimage.org/

https://postimage.org/app.php

https://postimage.org/

https://postimage.org/

Cheers Andrew

 

[L5wolvesf]

need pics to really answer the question correctly
they probably only need minor clean up but again w/o pics everyone is guessing including me

This plus like someone said it depends on where exactly the rust is.

 

[GasNSteering]

Electrolysis is the go, here is a set I did a while ago for my Landcruiser.

https://pixxxels.org/

https://postimage.org/

https://postimage.org/

https://postimage.org/

https://postimage.org/app.php



https://postimage.org/

https://postimage.org/

Cheers Andrew

Looks great. Did you have to prep them with any cleaners first?

 

[AJ.]

After the electrolysis it was just a wire brush and then some prepsol before paint.

Cheers Andrew

 

[joe_padavano]

We're talking a 1997 Explorer not a rare or exotic classic car that you can't get parts for. Be safe & buy new calipers.

The bore in the caliper casting is not a critical surface. The seal fits into a groove in the bore and is fixed. The piston slides in the seal and the piston is usually plated to preclude rust. That's why modern calipers are built this way.

To the OP: get a brake hone. Residual pitting on that surface in the bores is not critical. Just be sure the piston slides freely and the OD of the piston is smooth and clean. If the grooves that the seals sit in are in good shape, that's all that matters.

 

[Diesel Mercedes]

You can try dunking it in phosphoric acid to remove the rust, but I honestly wouldn't sand it or hone it.

Get remans or go the the scrap yard.

 

[apollo11]

You can try dunking it in phosphoric acid to remove the rust, but I honestly wouldn't sand it or hone it.

Get remans or go the the scrap yard.

Why?
I did honed them for years w/o any comebacks.
You only need to replace them if they are really bad.

 

[American Locomotive]

Because time is money, and calipers for most vehicles are very cheap. As mentioned the calipers for this Explorer cost $27. By the time you finish removing any rust, painting the caliper, cleaning the bore up, purchasing and installing new seals, etc... you're way in the hole.

For a rare vehicle with expensive $200+ calipers - sure, rebuilding makes sense. Not for an Explorer.

 

[apollo11]

Because time is money, and calipers for most vehicles are very cheap. As mentioned the calipers for this Explorer cost $27. By the time you finish removing any rust, painting the caliper, cleaning the bore up, purchasing and installing new seals, etc... you're way in the hole.

For a rare vehicle with expensive $200+ calipers - sure, rebuilding makes sense. Not for an Explorer.

Paint?
No, hone and replace seals. 10 bucks an axle at most and 5 minutes a caliper.
I did this for a living
I think I'd do a better job than a chinese child slave laborer

 

[American Locomotive]

Paint?
No, hone and replace seals. 10 bucks an axle at most and 5 minutes a caliper.
I did this for a living
I think I'd do a better job than a chinese child slave laborer

At the $90-120/hr labor rate for most auto repair rate - even 5 minutes on a caliper would make it a wash. Not to mention it's going to take a DIYer far longer than "5 minutes" to clean a caliper up.

It's not worth it for such a cheap caliper. Throw it out and get a new one.

 

[apollo11]

A DIYer may not have the money and if it wasn't worth rebuilding how did my boss make money?
The labor and parts were already built into the total.
And doing 4 at a time was easier than just doing one.
At 120 an hour, 40 bucks plus parts to rebuild all 4 is STILL much cheaper than say 27.00 a caliper times 4
A DIYers can rebuild all 4 for maybe 20-25 bucks
Your logic is flawed
It's my guess you are a parts-changer at best when it comes to automotive things.

 

[Mr_B]

If OP's calipers not that bad then bit of rust remover and or emery paper could be enough . For DIY rebuild always going be cheaper if calipers pretty serviceable condition .
If buying reman be sure buy reputable brand .

 

[American Locomotive]

A DIYer may not have the money and if it wasn't worth rebuilding how did my boss make money?
The labor and parts were already built into the total.
And doing 4 at a time was easier than just doing one.
At 120 an hour, 40 bucks plus parts to rebuild all 4 is STILL much cheaper than say 27.00 a caliper times 4
A DIYers can rebuild all 4 for maybe 20-25 bucks
Your logic is flawed
It's my guess you are a parts-changer at best when it comes to automotive things.

I can't find the caliper rebuild kit any cheaper than $10/caliper at all my local auto parts store. That's $40 in parts alone, and it's going to take a newbie significantly longer to do a rebuild. It's just not worth the time, when getting a new one at the parts store is so cheap. The new caliper one will be completely rust free, too.

Nice attempt at a character assassination too. I literally have a trophy on the shelf from Ford from an automotive diagnostics competition where you get penalized for swapping parts that aren't broken. Nice try though.

 

[WittHay]

Haven't rebuilt a caliper for a common car or truck in 20 years. For rust removal have always used emery cloth dipped in solvent. There is fine to coarse available. The solvent helps prevent scratching and if you keep dipping it, removes the rust from the emery cloth

 

[d.mcfarland]

A DIYer may not have the money and if it wasn't worth rebuilding how did my boss make money?
The labor and parts were already built into the total.
And doing 4 at a time was easier than just doing one.
At 120 an hour, 40 bucks plus parts to rebuild all 4 is STILL much cheaper than say 27.00 a caliper times 4
A DIYers can rebuild all 4 for maybe 20-25 bucks
Your logic is flawed
It's my guess you are a parts-changer at best when it comes to automotive things.

The "DIYer" would also need a hone which adds to the total. And if done incorrectly they can really mess things up, or not even actually rebuild the caliper properly.

 

[apollo11]

I can't find the caliper rebuild kit any cheaper than $10/caliper at all my local auto parts store. That's $40 in parts alone, and it's going to take a newbie significantly longer to do a rebuild. It's just not worth the time, when getting a new one at the parts store is so cheap. The new caliper one will be completely rust free, too.

Nice attempt at a character assassination too. I literally have a trophy on the shelf from Ford from an automotive diagnostics competition where you get penalized for swapping parts that aren't broken. Nice try though.

a participation trophy? ...LOL

10 bucks a caliper is still cheaper
do you have any math trophies?

 

[apollo11]

The "DIYer" would also need a hone which adds to the total. And if done incorrectly they can really mess things up, or not even actually rebuild the caliper properly.

depending on the condition, many times you don't and if you do, it's about ten bucks for a new hone
I don't know how many calipers you have rebuilt but they are so simple even child chinese slave laborers can do it

 

[Rusty67]

Ok guys, I'm not a pro mechanic but I've rebuild several calipers over the years against the better judgement of "professional" mechanics and never had a problem. I completely understand the argument. Many professional mechanics are just R&R guys and aren't proficient at rebuilding calipers so even if they can do it, it doesn't make sense because time is money. In that case, everyone's advice is bang on.

What a lot of people seem to be missing is that there are still mechanics out there who are proficient enough at rebuilding calipers to make it worth while if the parts are readily available.

Additionally, the home gamer still can save money doing it. Do you need to buy a brake cylinder hone for a few bucks? Yes, but then you have a tool you can use in the future. There are tons of jobs you can't do without a specialty tool that could cost you more than it would to have a pro do it for you or to replace what you are trying to fix but if you use the tool more than once, it pays for itself most of the time. I'm a little shocked to see the don't buy a tool attitude on this message board. We don't know the motivation behind the OP's question and we shouldn't assume one way or another what his financial state or mechanical skill level are.

Maybe the OP wants to rebuild the calipers because he has fun working on cars and this is relaxing for him. Ever met someone that finds scraping gaskets off an engine block on the weekends relaxing because their job is so stressful? I have. Whatever the reason he is asking for help, we should help and not say it is dumb for him to spend the time on it. I'm not saying that making a suggestion to buy a reman caliper is wrong, just that it should be given as an option and not forced down people's throats.

Now, to the OP's original question. When I rebuild calipers I hone the cylinder with a brake cylinder hone using bake fluid and hand finish with an emery cloth/brake fluid to remove any rust and smooth out pitting that the piston(s) can catch on. Then I check the cylinder with a clean piston to make sure there are no hangups. Once I'm happy with the way everything is moving in the bore I use brake cylinder assembly lube on everything and slap it together. Once it is together I like to test the caliper with pressure from my air compressor to make sure the piston still slides in and out of the bore properly before I install it on the car and bleed the system just to make sure everything is groovy. Also, if you have the cash, throw some steel braided lines on while you are at it =-)

 

[apollo11]

My thought is that a PRO wouldn't just swap out parts
he actually repairs parts too.

 

[L5wolvesf]

Ok guys, I'm not a pro mechanic but I've rebuild several calipers over the years against the better judgement of "professional" mechanics and never had a problem. I completely understand the argument. Many professional mechanics are just R&R guys and aren't proficient at rebuilding calipers so even if they can do it, it doesn't make sense because time is money. In that case, everyone's advice is bang on.

What a lot of people seem to be missing is that there are still mechanics out there who are proficient enough at rebuilding calipers to make it worth while if the parts are readily available.

Additionally, the home gamer still can save money doing it. Do you need to buy a brake cylinder hone for a few bucks? Yes, but then you have a tool you can use in the future. There are tons of jobs you can't do without a specialty tool that could cost you more than it would to have a pro do it for you or to replace what you are trying to fix but if you use the tool more than once, it pays for itself most of the time. I'm a little shocked to see the don't buy a tool attitude on this message board. We don't know the motivation behind the OP's question and we shouldn't assume one way or another what his financial state or mechanical skill level are.

Maybe the OP wants to rebuild the calipers because he has fun working on cars and this is relaxing for him. Ever met someone that finds scraping gaskets off an engine block on the weekends relaxing because their job is so stressful? I have. Whatever the reason he is asking for help, we should help and not say it is dumb for him to spend the time on it. I'm not saying that making a suggestion to buy a reman caliper is wrong, just that it should be given as an option and not forced down people's throats.

Now, to the OP's original question. When I rebuild calipers I hone the cylinder with a brake cylinder hone using bake fluid and hand finish with an emery cloth/brake fluid to remove any rust and smooth out pitting that the piston(s) can catch on. Then I check the cylinder with a clean piston to make sure there are no hangups. Once I'm happy with the way everything is moving in the bore I use brake cylinder assembly lube on everything and slap it together. Once it is together I like to test the caliper with pressure from my air compressor to make sure the piston still slides in and out of the bore properly before I install it on the car and bleed the system just to make sure everything is groovy. Also, if you have the cash, throw some steel braided lines on while you are at it =-)

Yes, exactly to all this

 

[sberry]

My helper just fixed a set on his own car the other day, didn't even buy new parts, just cleaned and put back together. I fixxed a wheel cyl on one not to long ago, it wasn't terribly old, the cup wasn't damaged, had a little rust and simy zinged a hone thru it a couple swipes right on the truck.
But if they needed parts wouldn't fug with it at 27$, would replace. I fix a lot wh when it's fast and I don't want to stop to get a part,, and it's going to work.
Fix expensive parts on old junk too.

 

[tym]

Ok guys, I'm not a pro mechanic but I've rebuild several calipers over the years against the better judgement of "professional" mechanics and never had a problem. I completely understand the argument. Many professional mechanics are just R&R guys and aren't proficient at rebuilding calipers so even if they can do it, it doesn't make sense because time is money. In that case, everyone's advice is bang on.

What a lot of people seem to be missing is that there are still mechanics out there who are proficient enough at rebuilding calipers to make it worth while if the parts are readily available.

Additionally, the home gamer still can save money doing it. Do you need to buy a brake cylinder hone for a few bucks? Yes, but then you have a tool you can use in the future. There are tons of jobs you can't do without a specialty tool that could cost you more than it would to have a pro do it for you or to replace what you are trying to fix but if you use the tool more than once, it pays for itself most of the time. I'm a little shocked to see the don't buy a tool attitude on this message board. We don't know the motivation behind the OP's question and we shouldn't assume one way or another what his financial state or mechanical skill level are.

Maybe the OP wants to rebuild the calipers because he has fun working on cars and this is relaxing for him. Ever met someone that finds scraping gaskets off an engine block on the weekends relaxing because their job is so stressful? I have. Whatever the reason he is asking for help, we should help and not say it is dumb for him to spend the time on it. I'm not saying that making a suggestion to buy a reman caliper is wrong, just that it should be given as an option and not forced down people's throats.

Now, to the OP's original question. When I rebuild calipers I hone the cylinder with a brake cylinder hone using bake fluid and hand finish with an emery cloth/brake fluid to remove any rust and smooth out pitting that the piston(s) can catch on. Then I check the cylinder with a clean piston to make sure there are no hangups. Once I'm happy with the way everything is moving in the bore I use brake cylinder assembly lube on everything and slap it together. Once it is together I like to test the caliper with pressure from my air compressor to make sure the piston still slides in and out of the bore properly before I install it on the car and bleed the system just to make sure everything is groovy. Also, if you have the cash, throw some steel braided lines on while you are at it =-)

Well said!

 

[sberry]

Depends on where one lives too. I will put a bush, a bearing, actually put some used brushes and a holder in an alternator the other day but reman parts have dropped in cost again. I scored a starter from the store the other day, got the old out, was going to take a peek then looked at the invoice, 36$, I wanted to finish , didn't feel like looking for parts, already had it in hand. Put the new on.
The alt I mention was a different matter, off color model, had another one i had saved, didn't need to look for a fussy part, it's going to outlast the truck, had it back together vs starting an adventure looking for another, different matter.

 

[sberry]

The modern world has its plusses, I hated rebuilding, took a lot parts stock, shopping, cost a lot. There is something to be said for being able to source good reman at the right price and nothing wrong with being a good parts changer, not everyone can do that right.

 

[AJ.]

Ok guys, I'm not a pro mechanic but I've rebuild several calipers over the years against the better judgement of "professional" mechanics and never had a problem. I completely understand the argument. Many professional mechanics are just R&R guys and aren't proficient at rebuilding calipers so even if they can do it, it doesn't make sense because time is money. In that case, everyone's advice is bang on.

What a lot of people seem to be missing is that there are still mechanics out there who are proficient enough at rebuilding calipers to make it worth while if the parts are readily available.

Additionally, the home gamer still can save money doing it. Do you need to buy a brake cylinder hone for a few bucks? Yes, but then you have a tool you can use in the future. There are tons of jobs you can't do without a specialty tool that could cost you more than it would to have a pro do it for you or to replace what you are trying to fix but if you use the tool more than once, it pays for itself most of the time. I'm a little shocked to see the don't buy a tool attitude on this message board. We don't know the motivation behind the OP's question and we shouldn't assume one way or another what his financial state or mechanical skill level are.

Maybe the OP wants to rebuild the calipers because he has fun working on cars and this is relaxing for him. Ever met someone that finds scraping gaskets off an engine block on the weekends relaxing because their job is so stressful? I have. Whatever the reason he is asking for help, we should help and not say it is dumb for him to spend the time on it. I'm not saying that making a suggestion to buy a reman caliper is wrong, just that it should be given as an option and not forced down people's throats.

Now, to the OP's original question. When I rebuild calipers I hone the cylinder with a brake cylinder hone using bake fluid and hand finish with an emery cloth/brake fluid to remove any rust and smooth out pitting that the piston(s) can catch on. Then I check the cylinder with a clean piston to make sure there are no hangups. Once I'm happy with the way everything isc moving in the bore I use brake cylinder assembly lube on everything and slap it together. Once it is together I like to test the caliper with pressure from my air compressor to make sure the piston still slides in and out of the bore properly before I install it on the car and bleed the system just to make sure everything is groovy. Also, if you have the cash, throw some steel braided lines on while you are at it =-)

Thanks, saved me a lot of typing

Cheers Andrew

 

[American Locomotive]

a participation trophy? ...LOL

10 bucks a caliper is still cheaper
do you have any math trophies?

$10/caliper for seals. $15 for a brake cylinder hone. 30 minutes per caliper to disassemble, clean, and re-assemble (remember, not talking a pro that does dozens of calipers a day, and the new calipers are rust free)

So we're $35 and 1+ hour into labor messing around with some old crusty calipers. When for just $19 more I could get the job done faster for a lot less hassle.

My thought is that a PRO wouldn't just swap out parts
he actually repairs parts too.

A PRO does what's best for the customer. In this case the replacement calipers are dirt cheap. A pro would be costing the customer more time and money by dicking around trying to rebuild some janky caliper.

Like I said, on some vehicles it makes sense. For an Explorer it doesn't.

I fixxed a wheel cyl on one not to long ago, it wasn't terribly old, the cup wasn't damaged, had a little rust and simy zinged a hone thru it a couple swipes right on the truck.

Yeesh, no way I could ever, ever be bothered to fix a wheel cylinder. I think the most I've ever paid for a wheel cylinder for ANY car was like $9. Most of the stuff I work on, wheel cylinders are typically $5-7.

 

[d.mcfarland]

$10/caliper for seals. $15 for a brake cylinder hone. 30 minutes per caliper to disassemble, clean, and re-assemble (remember, not talking a pro that does dozens of calipers a day, and the new calipers are rust free)

So we're $35 and 1+ hour into labor messing around with some old crusty calipers. When for just $19 more I could get the job done faster for a lot less hassle.

You are 100% correct. The saved labor time is why most shops will swap calipers instead of rebuilding, well that and you can't warranty the time to rebuild a caliper again I guess.

He is saying if he has to do his own then yes he saves $40 or whatever, but still is missing the point that some people value time at a certain dollar amount.

 

[kkroger]

Bead Blast is really the only good way... Glass Bead then rinse with water, blow it all off, then clean with brakleen then assemble...

 

[sberry]

The fix was fast, faster than replacement. No procurement cost.