Caliper rebuild: install rubber seal

[chicane]

I am rebuilding my calipers. I am having a time getting that last bit of rubber seal to seat in the lip around the piston. I have been creating all sorts of wooden and plastic tools, I also have some small metal tools but I cannot get that piston dust cover all the way on. Any advice is appreciated.

 

[cas2395]

Use an air compressor. Blow air into the hole for the brake line while your holding the piston over the hole..
sometimes you have to wiggle the piston a bit to get it to jump over the piston.

 

[gjz30075]

Try lubricating it with brake fluid. Small amount.

 

[Harrison2]

have you used any rubber grease?

 

[chicane]

I could push it in if I could get to it but it is the backside of the piston, the part facing the carrier so I can't get a tool in there.

 

[gayler]

As a couple of guys have said lube it up with brake fluid and hold the piston up to the seal. use a rubber tipped blow gun and blow air into the hole for the brake line. The outer seal or "boot" will balloon out around the piston. Good luck, it should go pretty easy.

 

[Milton Shaw]

Install the seals in the caliper first make sure it is in the grove all the way around. Lubricate with brake fluid or caliper rebuild fluid. Then use a rubber tipped blow gun to put air in the line fitting hole while you position and push the piston down into the bore. Should press in with just hand force after the boot is stretched over the piston and air is not blowing.
I also after assembling the pads and calipers on the rotor, use the blow gun again to preposition the pads against the rotor ready to have a full pedal. Also if the master cylinder is kept full you can leave the bleeder screw open until fluid comes out and eliminate most of the pumping problems of getting air out of the system. I block the line in the brake hose with a piece of rubber tubing while I am rebuilding the caliper to keep from getting empty master cylinder and air in all the lines.

 

[chicane]

Great video. Silicone Grease is that kosher?

 

[theoldwizard1]

Great video what is the assembly lube he is using? It looks like Petroleum Jelly.

Not Petroleum Jelly. Silicon grease ?


EDIT : I found these 2

 

[chicane]

Not Petroleum Jelly. Silicon grease ?

This stuff:
http://www.amazon.com/dp/B000KXLR5E/?tag=atomicindus08-20

 

[chicane]

Not Petroleum Jelly. Silicon grease ?


EDIT : I found these 2

So this stuff can be used on the internals like the piston itself as the guy did in the video?

 

[andrew240z]

Use an air compressor. Blow air into the hole for the brake line while your holding the piston over the hole..
sometimes you have to wiggle the piston a bit to get it to jump over the piston.

This

 

[Jarhead0408]

chicane,

I had the same dilemma last week.

Here's what I did, it's not much easier, but it worked for me.

I fastened the whole caliper in my vise so that I could load the piston from the top.

Then with my wife to help me, we used two sets of 45 degree bent nose pliers (Needle Nosed) and opened them to spread the rubber seal.

I then used a small jewelers tool that looks like a small spoon on one end (Smaller than a 1/4" across.) to slip inside of the rubber seal and work my way around it to pull it in place.

Be careful not to rip that rubber.

It'll take some patience, but it works. I couldn't get it done by myself no matter how much I tried. I just needed a 2nd pair of hands in addition to the vise.

 

[moclan]

just rebuilt a set for a vw golf gti (mk1). After splitting 2 of the dust seals this is what I did.
first everything is clean and a little lub of red rubber grease (castrol) on the piston and caliper grooves and on the seals. Installed the seal in the caliper, then installed the dust seal on the piston, into it's groove. Made sure all was fine and then pulled the dust seal out of the piston groove whithout taking it of the piston, slidding it back till there was enought dust seal to put into the caliper groove. Finger pushed it into the caliper and once seated properly pushed the piston into the caliper, a few twists to get the piston into the caliper seal. Once the piston has started going in I pushed the dust seal towards the front of the piston (and the groove). The lip of the dust seal just "falls" into the groove. double check. done

 

[chicane]

Not Petroleum Jelly. Silicon grease ?
EDIT : I found these 2

I went to the store and the CRC stuff is specifically not able to lubricate internals like the rubber or seals, it is for the guide pins and stuff like that. It is a black grease not that clear silicone.