Banjo bolt sealing- anyone have any good tricks?

I should never be asking a brake question. I used to work on brakes for a living, and was certified. I've had plenty of banjo fittings that didn't want to seal, but this time is the worst ever.

I cannot get the bolts to seal up at the wheel cylinders on my '51 Chevy. Before anyone asks the obvious "did you use the little copper washers?" Yes, I sure did. I also made sure the bolts and surfaces were good and clean. I've tried the old copper washers, and a couple of different sets of new ones. I've also tried new bolts. I've tried tightening the shit out of them (a little at a time) up to the point of even twisting one in two. The leak is between the block and the wheel cylinder. FWIW, these are the original wheel cylinders that are rebuilt.

Anyone have any ideas before I bite the bullet and buy new cylinders?

 

i've used the washers that have a rubber o-ring fused to the washer. the place i bought them called them lock-o-seals. hope it helps.

 

copper washers

 

x2 on the washers with the rubber ring, thats what Cummins uses on diesel injection pumps so you know they gotta be good.

 

Here's a tip-
Make sure all surfaces are FLAT, even if that means a touch up with a file.

Use copper washers (sorry).

Instead of relying on simple bolt-torque to compress the washers, I often take a small brass or plastic hammer to help compress the copper by tapping the top of the bolt while I tighten.

Use good sense of course, so you don't break or damage anything, but if you use the tapping on the bolt-head to do the gasket-compressing, you end up with a much better seal without stressing the bolt a whole lot. Tap while following with the wrench to keep things snug.

That should seal anything that isn't lumpy or wildly out of whack.

ONE MORE THING- I found once that the "smashed-collar" part of the fitting, you know, the part that looks like a skirt around the rubber hose, was too large diam to fit inside the recess on a caliper, and didn't let the "Banjo" sit flat on the caliper surface, so the banjo was cocked slightly at an angle. So I used two washers between the banjo and the caliper to take up the space and let them sit flat.
One other time in that situation, I took a vice grip and put a flat spot in that "skirt" to let the banjo fit inside the caliper recess. That worked too.

 

dare..different makes good points. if all else fails contact these fellers and inquire about the loc-o-seals. i used them on my '58 duo and my '82 wideglide. no matter how much i touched up the surface of the '58 master cylinder it just would not seal. when i did the '82 i used them the first time it went back together and never had a problem. good luck.
Use our new toll free phone numbers to contact us

Okla. City Tulsa
1-888-OKCSEAL 1-888-SEALTUL
(1-888-652-7325) (1-888-732-5885)

 

I did a bit of research on the lock-o-seals. They're made by Parker. We have a distributor here locally. Apparently, I want part number 800-8315-7/16 That's a seal with the rubber rated for brake fluid, aluminum carrier, and 7/16 I.D.

 

Sounds to me like either the banjo surface isn't square to the block surface when the bolt's tighened down or else the concentric grooves are worn away and aren't digging into the copper washers.

You might also check the wheel cylinder surface to make sure there are no burrs on it.

 

Have you tried thick copper washers? I know this sounds stupid, but generally the thicker washers are slightly softer.Try annealing a pair of washers, by heating with a torch and allowing them to air cool slowly this trick has got me out of a corner a few times. Also make sure that the mating surfaces are flat and clean with no nicks, burrs or radial scratches.

 

|Is the bolt in the banjo bottoming out before the head tightens enough on the sealing washers, I've had the happen to me once the union seemed tight but leaked, I shortened the bolt by a couple of threads to cure, the pattern replacment hose banjo was slightly thinner than the original plus thinner copper washers, hence my previous comment about thick washers.

 

try Dowerty washers.

 

i'll second the annealing suggestion before you buy the o-ring type.

 

Don't file the sealing surface - scrape it using a new Stanley knife (craft knife) held square to the surface. If you use some engineers blue or colour it in using a sharpie before you start to scrape this will give you a good guide to what's square and what's not.

 

Cymro- I did try shorter bolts, also. The annealing sounds like a good idea that I have not yet tried.

 

I finally bought a box of copper washers and never reuse the old washer they might work reused , might not , New washer each time , they are cheap insurance,,,,

 

I've been struggling with this. One caliper I tossed because I was sick of fooling with it and the replacement sealed fine. The other I replaced the copper washers with some that were slightly bigger. The old ones were real tight around the bolt, this was looser and so far seem to work.

These have been a big headache. I thought I was the only one that had a problem with them!

 

^I've never had a probglem for more than a half hour with any before. These have been kicking my ass and making me wear a dress. I will win, though.

 

You'll beat it.

I threw parts at it, switched to braided steel lines, and finally got sick of fooling with them and did other stuff for months.

I have to swap out mc/booster right now, but if this problem shows up again I'll swap that stupid caliper out and the banjo bolt and see if that gets me anywhere.

I tried to spend as little money as possible, then got to the end of my rope and figured if it costs $100 to get these fixed and helps save my sanity, its money well spent.

Also, I've learned the value of a lifetime warranty!

I've gotten 'deals' on internet parts, but they were worthless as they had problems and weren't worth postage to return.

 

Im wondering if the ID of the "tighter" washers got even smaller as they were compressed and they distorted as they were forced against the banjo bolt?

 

OK- problem is solved. Decided to try annealling some washers before going to the O-ring jobs. After having trouble even FINDING more washers (does anyone else think that it's bullshit for the parts store to try to make you buy an assortment pack of 8 washers to get TWO that you need and can use?) I found some loose ones mid week. I annealled them (glad I bought extras, as I puddled a couple) Put them in today, using the gradual torquing/tapping method. And got a good seal.

Now, it's on to front brakes/front suspension and rewiring- then I can drive this girl around a bit before diving headlong into the bodywork/restyling.

Thanks to everyone who posted the good ideas. Hopefully, this thread will help others through the search function.

 

Thanks for the update. I agree its hell finding those things, and depending on the place they try to charge you an arm and a leg for them.

 

I've had really good luck finding copper washers, in the correct size and thickness, at both Lowe's and Ace hardware. I always anneal the washer prior to use. If you're trying to use the old washers, you'll find that they are work hardened, and don't want to seal. Anneal them, they'll work great. Oh yeah, I forgot to mention, I fully agree with the annealing suggestion.

 

^ Oh, I'm a big time believer in annealing, too. Well, I am, now. Everything you said about work hardening on the old ones makes perfect sense, especially considering how easy copper gets hard and brittle with work. But, in the past, I've always had better luck with reusing than replacing them. I'm not sure why, but that's my experience.

But anyway, now that the frustration is over, I'm ready to charge ahead on the girl. Felt good to fire it up and drive it out of the garage, even if it was only to turn it around.

 

Thanks all, this post saved my bacon and my sanity, as I've never had such an uncooperative pair of calipers/lines (napa basics, '69 GM A Body). If your local parts guy was out of copper washers last month, (apologies) it was me.
Steps used, but not limited to:
- Mild file work on one of the two caliper's casted shoulder nubs that hose crimp was touching when dry seated. I wanted to avoid any interaction there as I tightened. Why would such a drastic casting variation exist on the R caliper, but not the L? All part of the fun! Part numbers were confirmed for the application.
- Mild file work across _caliper_ banjo mating ribbed surface. I didn't want to reduce the profile of these but repeated overtighting (as the madness set in) gack'd these anyway. Fun fact - in a pinch you can get away with these ribs basically missing!
- Two annealing sessions on washers with a plumber's mapp torch, cherry red, but working the flame around progressively to avoid uneven heating as they reddened.
- (Naughty) A very conservative smear of permetex sealer I normally use on carb fuel lines that won't behave. Just between copper washer and caliper. Tried to keep it out of inner washer surface.
- Caliper in vise, washers still warm, box wrench to slowly turn banjo bolt while gently but firmly tapping squarely on bolt head with a dead blow rubber mallet. After re-washering these fittings 100 times with final turns via torque wrench, I just did this by feel.

 

The sealing surfaces on a banjo fitting depend on compression forced on it by the threads of the banjo bolts.
Once you visualize that, you can understand why sometimes people will strip the threads while trying to clamp it hard enough to stop any seepage.
What I do is to encourage that clamping force without over straining the threads.
When I have a box wrench on the bolt head, I take a brass or plastic hammer and use many medium taps on the bolt head as I tighten the wrench. With each tap, the wrench will advance a little with a moderate pull.
What that does is to "set" the sealing surfaces or copper washers into each other for a good seal without relying on the threads to do all the pulling and over-straining.
That makes the surfaces sit flatter to each other without over taxing anything.
Just use good judgement not to beat it to death while encouraging a good gasket seal.
It works great for me even on used fittings that have previously leaked.

WHY BE ORDINARY ?

 

Some good tech here. I'm fighting this battle right now.

 

If possible I have a really sharp small flat file I run across the sealing surface. Most of the leaks I encountered were on cast iron master cylinders which almost always were solved with the file.

 

I’m sure some people will disagree but:
1. Never reuse the copper washers if the surfaces weren’t flat before even though it sealed the the first time copper washers are now distorted and will not go back together the same way.

2. Don’t over tighten it only distorts the banjo fitting and makes the problem worse. If the surfaces are clean and flat it doesn’t take much torque for it to seal. I’m sure there are some charts/tables for proper torque.

3. I always put a dab of oil on the banjo threads and rub both sides of copper washer between my fingers with oil/ brake fluid, it allows the banjo bolt and washers to go together smoothly without scoring the surfaces.

The copper washer is softer and supposed to deform to take up differences of flatness but does little if surfaces are scored or dirty. You mileage may vary.

 

I've reused hundreds of copper washers on aircraft spark plugs over the years. We'd save up a hundred or so, then string a bunch on a piece of safety wire, heat them red hot and dunk them in cold water 'til they stopped squealing. Worked well as long as you didn't get them so hot they melted....

 

Warbird, isn’t heating and quenching the recipe for tempering? Basically the opposite of what we want a soft sealing washer to do?