Rear left brake caliper banjo leak issues!
 

Hey All,

So my car is still grounded due to brake issues :banghead:

I have finally narrowed it down to a leak on the rear left (USA drivers, or JDM passenger) brake caliper.

The issue is that when I torque the brake line banjo bolt to the caliper the crush washer is remaining flat and not sealing.I am getting a nice "ring" shaped indentation on the both sides of the crush washer by the bolt head and on the line side of the one by the caliper. But the side that sits against the caliper is not crushing at all, or at least it is not showing any signs of indentation.

I have tried two calipers now, both with the same result. Have I just been unlucky and got two calipers with the mating ridge worn away or am I missing a trick? The rear right has sealed nicely both times.

Has anyone else had this issue and if so how did you solve it?

Thanks, Tom

-New, proper thickness crush washers?
-OEM banjo bolt? Does it bottom out or can you put more torque on it?

If the banjo bolt bottoms out without crushing the washer that would lead me to believe the banjo is either too long or too thin of washers are being used. If both of these are correct, inspect the sealing area on the caliper itself where the crush washer sits. On countless reman calipers I have seen this area is smooth WITHOUT ridges which will never bite into the crush washer.

See this picture from Rock Auto, notice where the crush washer goes are rings. These bite into the crush washer and again I have received countless reman calipers where the rings are all smooth and worn away.
https://www.rockauto.com/en/moreinfo...386794&jsn=526

Thanks for the response - much appreciated.

The banjo bolt used should be the correct length as these calipers were good non leaking used from a reputable member on here. They had lines attached that I had to remove to fit with the SBG rear kit spacer, so perhaps that removal was the final straw for the mating rings.......there is nothing visually as pronounced as your pictures show.

FYI, of the 4 sides of the two washers, three are crushing and making very clear rings. The only one staying smooth is the side that touches the caliper. Leading me to believe the issue is that the mating rings are gone. Which upon visual inspection seems to the the case.

Is there any solution to this other than the costly roulette of buying calipers until you get a good one?

I guess I can try to get some thicker washers and see if that helps, but as hard as it is to believe; the nearest store that has them is 50 miles away......

.........yes I really do live in buttfuck nowhere :banghead:

The copper washers should crush and seal under little force, however you can try tightening them more. Worst case is you crush a washer too much and your back where you started, with a leak.

If you are re-using old copper crush washers, they need to be annealed first.

You're having a good run, :crying: have the lines been replaced? If they have, might check the height of the banjo v stock, the washers might have been torqued down a few too many times and extruded a bit too. I'd follow Brekyrself's advice first and anneal. Would think not out of the realms of possibility a hardware store carries them or, better yet, some hydraulic/earthmoving/farm equipment supply if there's any of those around.

I notice most of the recent SS brake sets don't have the locating pin used by the stock, made to measure - using stock ends - and earlier Japanese ones, which helps when torquing them down.

McMaster-Carr carries crush washers.

https://www.mcmaster.com/#standard-crush-washers

Nope, worst case is that I snap the bolt....like i just did.......:pat:

I am only using new washers in an effort to eliminate them as the issue.

Thanks for the advice though!

Yeah, a good run is one way of putting it......I am trying hard to remain patient.......the love/hate with this car was tipped so far into the hate with the damage it has done to my bank account it's not funny anymore.....i just want to get it on the road and "enjoy" it to see if i can begin to like it......

Lines are brand new SS from SBG that came with the rear brake kit I installed. So I am assuming that they are not the issue......but seeing as I just snapped the bolt, i will be re installing the old lines with new washers and will see if by some miracle that helps.....

Thanks for the support!

Thanks, will try them if I can't source locally.

https://cimg6.ibsrv.net/gimg/www.rx7...98d2e9f45c.jpg


Had a gander at a few rear calipers here, smooth as a baby's bottom where the banjo sits, other than a small counterbore. I suspect your banjo is 11/32" thick, no stock lines handy, but think they're around 9mm wide, so virtually no difference if that's the case. The stock bolt will screw in well beyond that difference in thickness before bottoming, somewhere around 3mm, if the sakebomb bolt is around that much longer, I could see that causing issues.

As you probably know crush washers create a seal by deforming to near perfectly match their mating surfaces. That requires the metal to be soft. When a metal like copper experiences a permanent deformation, a process known as strain hardening is happening. It's actually a pretty cool phenomenon that has to do with metal crystals and molecules and shit, but it sucks when you're trying to make a seal because the metal is not as ductile as it used to be.

Take an old copper crush washer and try to bend it, then compare it to a new one... it'll fold right in half with little effort. You can re-use a hardened crush washer by heat annealing it. All you need is a propane torch and your eyes. Heat it to a dull (not glowing orange!) red color all around. Let it cool naturally. Back in business and no need to buy and wait for a pack of 100.

Definitely a good idea to check that the length is correct.

Steel vs copper in the same application my money is on steel for sure. Trying to compress a work hardened copper washer with a hollowed out and cross drilled steel fastener... that could go either way.

So it looks like I have solved the problem. Brakes are working great with no leaks I can find :icon_tup:

The issue seems to have been the crush washers themselves. Not sure if I got a "hard" batch but I got some from a different source that were considerably thicker and seemed softer. I guess this has allowed them to fill all the tiny imperfections and provided a proper seal.

As for bolt length, all my bolts, including the ones from SBG were the same length. I believe I snapped a bolt because I had crushed the "hard" washers as far as they would go, then the extra torque snapped the bolt where the holes are.

I will keep you all posted if I have any further issues.

Thanks fro your help!

Congrats on getting to the bottom of the issue. That's always a good feeling.