Banjo Fitting washers?

[N_Jay]

I have always seen banjo bolts with annealing copper or aluminum crush washers.

My lift has the washers with the rubber seal on the inner edge.

I need to replace one that was lost during install.

Searching Amazon, the call the rubber lined ones "fuel system" washers.

Any reason to not use them?

Any thoughts on which is better for what applications?

 

[BrandonV]

Maybe call the company and see what they say about getting a replacement?

My biggest concern with a fuel system washer is that the rubber might be designed for exposure to fuel and not hydraulic fluid.

 

[N_Jay]

Not too worried about the rubber, since "fuel" (Diesel and Gasoline) are far stronger solvents.

More about the design.

Is there a pressure limit where one is better?
Is it just an improvement, and most solid can be replaced with the rubber lined?

 

[BrandonV]

The metal to rubber bonded washers should be sufficent. In theory I think they're supposed to make a stronger seal assuming chemical compatibility.

What I would probably do is not order them off Amazon but rather a place like McMaster-Carr where the quality is most likely a much better known variable.

 

[CraigStu]

And replace both of them. I assume auto brake systems run higher pressures but every time I have had a seep, using new washers solved it. So I stopped re-using seal washers especially on banjo fittings where the bolt has very little metal so you can't just crank it tighter.

 

[Wrench97]

Hydraulic cylinders use them, grab one from a local hyro shop.

 

[N_Jay]

Yes, these are on the hydraulic lines to the cylinders.

You NEVER reuse hard crush washers, or the folded type (the ones that look like spark plug washers).

Stil wondering what the decision point is between the two types.

Also kind of Wondering if you can reuse them since you are not crushing the rubber part.

They are almost like rubber O-rings with the washer part defining the amount of crush and preventing over tightening.

 

[Wrench97]

I have reused them before on hydro lines, but I believe it best to replace if possible.

 

[Firebrick43]

https://www.parker.com/literature/Packing/Packing - Literature/Catalog_CompSealingWashers_PDE3358-GB_1103.pdf

On banjo fittings the area is smooth and you want to use the WO style bonded washers.

The shape of the rubber is not oring shape except on the WO style.

You can reused copper sealing washers by heating to a dull red in low light and dunking in water to anneal the copper. The folded type should not be used.

I don't find much advantage of the oring style if the surface quality of the banjo housing and the port is good and the copper washer is annealed.

If the surface finish is not ideal, as long as there isn't significant radial scratches from the port, then the bonded washers will reduce seeping.

Bonded washers should not be reused.

 

[bwringer]

Replace, unless you're five miles underground in a mine outside Kuala Lumpur, and this is your last desperate chance to get to the surface...

These are sometimes also called "Dowty" washers.

And yes, get them from McMaster or another reputable supplier, not frickin' scAmazon... have you seen the nauseating things hydraulic leaks can do to flesh?

 

[N_Jay]

So what I am hearing is they are an improvement over annealed washers in most applications.

I'm putting 2 new ones in. The inner one seems to have dropped out when the hose was connected and ended up on the floor and well stepped on.

This is just the first time I have seen them.
Not sure how high pressure the system is.

 

[BillK]

I would want to use whatever the system was designed for. In your case the washers with the rubber.

 

[esben57]

Knew them as Dowty washers or Dowty seals.

 

[finn]

You’re overthinking this.

While the washers with the elastomeric seal may be preferred in high cycle industrial operations, they’re really boot and suspenders for a homeowner lift.

Billions of plain annealed copper seals are used on car and truck braking systems and Diesel fuel injection equipment without issue. I would think most lifts use them, too. At least all three of mine do.

I could see using the elastomeric seals in food processing equipment, or other manufacturing equipment where contamination could cause health issues, but it seems unlikely to be an issue in garage equipment.

 

[N_Jay]

Not as much overthinking, as trying to learn.

Going with what was on there as even with one missing it doesn't seem to be leaking.

 

[Wrench97]

Some fittings are designed with a bevel the oring seal crushes into

 

[N_Jay]

Some fittings are designed with a bevel the oring seal crushes into

Where is the bevel in a banjo fitting?
I always thought that the surfaces were flat and parallel.

 

[Wrench97]

Some of the oring style hydro cylinders have a bevel at the top of the hole and the bottom of the fitting at the hole for the oring to squeeze into, the metal washer is to hold the ring in place, others like on A/C lines are just flat and the washer holds the oring from blowing out.

 

[andyvh1959]

Not too worried about the rubber, since "fuel" (Diesel and Gasoline) are far stronger solvents.

More about the design.

Is there a pressure limit where one is better?
Is it just an improvement, and most solid can be replaced with the rubber lined?

Depends on the fuid in the system. Banjo fittings are common to brake fluid systems, and the seals in braking systems are typically EPDM material. Seals for fuel/diesel/gas are typically Nitrile or Neoprene which are NOT compatible with brake fluis systems.

Banjo fittings/washers seal on a flat spotface, not into any sort of bevel on the port face or in the port. Most banjo fittings do not require a bonded seal washer, but instead use copper or aluminum crush washers, again mostly becaue of brake fluid compatibility but also to withstand the high heat ranges possible in braking systems. Fuel/diesel/gas not so much for high temp.

 

[N_Jay]

I didn't think of temp as one of the decision points.
That makes sense.
As does differing fluids, but most oil/fuel fluids are compatible with the same materials.

 

[Firebrick43]

Some of the oring style hydro cylinders have a bevel at the top of the hole and the bottom of the fitting at the hole for the oring to squeeze into, the metal washer is to hold the ring in place, others like on A/C lines are just flat and the washer holds the oring from blowing out.

Those are SAE/ORB fittings

 

[lolaetype]

Maybe call the company and see what they say about getting a replacement?

My biggest concern with a fuel system washer is that the rubber might be designed for exposure to fuel and not hydraulic fluid.

I agree with Brandon. Contact the manufacturer. I'd be surprised if they don't sell replacements.

 

[ChevyEFI]

I am going to have to remove and re-anneal brake hose washers. Darn. There goes my weekend.

 

[finn]

I am going to have to remove and re-anneal brake hose washers. Darn. There goes my weekend.

Several that I have seen recently aren’t really reusable. The face of either the caliper or banjo block (don’t remember which) has concentric ridges stamped or machined into the face. These ridges permanently deform (or indent) the sealing surface of the copper sealing washer.

 

[Firebrick43]

If

I am going to have to remove and re-anneal brake hose washers. Darn. There goes my weekend

It will only be because of your misinterpretation of what the response was in reference to.

 

[Wrench97]

I am going to have to remove and re-anneal brake hose washers. Darn. There goes my weekend.

Just tap the bolt with a small ballpeen and retighten you'll be fine.