Rear disc brake caliper line leaking at seal...tried different combinations...help! (1 Viewer)

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I have a 1974 FJ40 with a rear disc brake kit from SOS Performance and am having problems getting a good seal on the right rear. That is the only one with a problem, and this is the first time in my 20 years of wrenching to have this problem. The SOS caliper is a 2005 Toyota Sequoia, and the one they sent had a machined surface for the banjo bolt and came with a banjo bolt and copper washers. It leaked from the banjo fitting, and after making sure I hadnt crossthreaded it and used new washers, I tightened it down until it didnt leak anymore from the washer-to-caliper seal. Except it never stopped leaking and the threads stripped out with what I would estimate at ~25 ft-lbs.

So I contacted Tom at SOS and he offered to send a new caliper for shipping cost. Well, I am in Canada so that shipping and import is always unreal. So Tom gave me a NAPA part number and I went down and bought another right rear 2005 Toyota Sequoia caliper for another $225. This one came painted only and has a rough cast surface for the banjo bolt seal. It came with a banjo bolt and new copper washers. I used that bolt and new washers but sure enough it leaks from the caliper-to-washer seal. I can tighten it down to ~60 ft-lbs and it still leaks (but at least didnt strip the threads like the SOS caliper. I did notice that after ~5 of the ~10 turns the bolt goes into the caliper that it got noticably harder to turn but still went in another 5 turns. It didnt feel right though, like the threads had paint on them or a rough tap.

I thought maybe the bolt was bottoming out in the caliper but its not. I also tried doubling up new washers and no good.

Here are some pics. Yes, in this one I had the neck of the banjo fitting outside the "fingers" but that was just another try in that position after first trying it in between. I wanted to see if the neck was bottoming out in the fingers and effecting the seal but thats not the case either.

You can see the pattern of the casting on the washers.

I am at a loss, appreciate your thoughts pls.

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65swb45

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Measure the banjo fitting at the side closest to the hose, and the side furthest away. The easiest explanation is that the two surfaces are not parallel, and that the runout exceeds the ability of the copper washers to compensate for.
 
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It could be that the washers are simply too hard and are not compressing. The only solution would be new washers from a different source that hopefully soft enough or anneal the washers you have. Annealing would require you to heat them up to red hot without melting them and then allowing them to air cool. Don't drop them in water or oil or you will have hardened them. The air cooling keeps the metal in a softer state and will allow them to crush and seal like they should.
 
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In the end I had to find a washer with a larger than 10.3mm ID that would sit against the caliper and stack that with a thick copper 10.3mm washer. The culprit is the crappy casting marks on the capilers and lack of machining at the banjo mating surface.
 

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