wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) PowerDork
6/11/22 6:10 p.m.

I'm doing a disc swap on my 93 Cummins Dodge with a Dana 70. I'm having problems with my "bolt on" kit. The latest is the banjo fittings on the calipers leal like sieves.

This fitting right here:

Calipers are off a very limited run of ElDorados that used 4 wheel disc brakes (I'm thinking the Toronado based ones). Very rare, and the 4X4 community has snatched up most that are out there, because the e-brake is mechanically self adjusting. But nevermind all that. I'm guessing the cure is some sort of stock GM soft line away.

On either side of the banjo fitting, goes a copper washer, designed to squish, and make the seal. The mating surface of the caliper has a series of concentric ridges emanating from the mounting hole. I'm no Scientologist, but I believe those would screw with the brass washer's sealing mojo, right? I have put maybe 50 ft/lbs on the banjo bolt, and fear I'll shear it off if I go after it any more.

I'm guessing GM makes a soft line that threads into the caliper, sans banjo bolt, and fits a standard 3/8" flared end on the other, approximately 12" long. Can anyone confirm or refute this idea? 

Here's another picture for the heck of it.

 

 

 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
6/11/22 6:17 p.m.

The concentric rings help the crush washer seal. Is it weeping, or gushing? If weeping, try new washers. 50 - 55 ft-lbs is probably safe for a cast iron caliper. If it's gushing, maybe the banjo bolt is a touch too long? If you have the means to do so, you might shorten the threaded end of the banjo bolt by 1/8", just to be sure it's not bottoming out inside the casting before you've adequately crushed your washers.

 

eastsideTim
eastsideTim PowerDork
6/11/22 6:19 p.m.

Not sure about switching away from the banjo bolts, but I have run into situations where the copper washers that came with a brake hose or caliper were crap.  I think I replaced them with Dorman ones from the local parts store, and they sealed up fine,

SV reX
SV reX MegaDork
6/11/22 6:37 p.m.

Crud on the mating faces of the crush washers?

I like AC's theory about a bolt that's too long...

SV reX
SV reX MegaDork
6/11/22 6:39 p.m.

Did you use new crush washers, or try to re-use the old?

APEowner
APEowner SuperDork
6/11/22 6:48 p.m.

Banjo fittings are a pretty tried and true way of connecting brake hoses to calipers.  The OEMS use a variation on the banjo fitting as shown below.  Concentric circles on the sealing surfaces are pretty standard as well.  The surfaces have to be parallel, clean and unscratched.  The bolt also has to go in perpendicular to the caliper.  If all of that is true and you've got fresh washers on there it'll seal.

NOHOME
NOHOME MegaDork
6/11/22 7:32 p.m.

Sand the washers on a flat surface until the sealing surface is smooth. Heat them up good and toasty with a torch as that make the copper soft (annealed). Retry. Check the other surfaces to make sure they are clean.

That is what I do when using old copper washers. If the parts came from china, I might question the metalurgy since copper is not like gold.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) PowerDork
6/11/22 8:20 p.m.

Thank You, everyone. New washers, dripping, not gushing. Excellent info on the concentric circles around the port. I'll measure, and likely lob a fat 1/16th off the bolts in the morning.

Yep, Iron calipers and banjo bolts. I definitely hadn't considered that the bolts might be too long. Thanks, GRM

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
6/11/22 8:38 p.m.

It used to be SOP to reuse the washers because the new ones that came with a caliper were often the wrong size and would leak.  To make myself feel better I would reverse them so the side crinkled by the ridges faced the other way.

 

Looking at the pics, your fancy braided hoses' ends are bottoming out on the caliper.  You can fix this by doing a lot of clearancing, or just add a second washer on the caliper side of the hose.

Patrick
Patrick MegaDork
6/11/22 9:11 p.m.

In reply to Pete. (l33t FS) :

Banjo fittings look backwards,  no?

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
6/11/22 9:15 p.m.
Patrick said:

In reply to Pete. (l33t FS) :

Banjo fittings look backwards,  no?

Hmmm, it is possible that the banjos are not symmetric. I can't tell from the pic.

Patrick
Patrick MegaDork
6/11/22 9:27 p.m.

In reply to AngryCorvair (Forum Supporter) :

The hoses specific to the original application are not symmetrical, i have them on the back of a couple cars

APEowner
APEowner SuperDork
6/11/22 9:27 p.m.
Patrick said:

In reply to Pete. (l33t FS) :

Banjo fittings look backwards,  no?

I think you may be on to something there.

triumph7
triumph7 HalfDork
6/11/22 10:43 p.m.
NOHOME said:

Sand the washers on a flat surface until the sealing surface is smooth. Heat them up good and toasty with a torch as that make the copper soft (annealed). Retry. Check the other surfaces to make sure they are clean.

That is what I do when using old copper washers. If the parts came from china, I might question the metalurgy since copper is not like gold.

The proper method to anneal copper is to quench it in water after heating.  Unlike steel where you let the part cool slowly.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) PowerDork
6/12/22 7:19 a.m.

Again, thanks for responses, everyone. The banjo ends have maybe a 10 degree bend that really only works when bent away from the caliper. It may be possible to get it on the other way, but I have tried repeatedly and failed. 

Good to know the other info presented here. I'll give it another go around shortly.

NOHOME
NOHOME MegaDork
6/12/22 8:01 a.m.
triumph7 said:
NOHOME said:

Sand the washers on a flat surface until the sealing surface is smooth. Heat them up good and toasty with a torch as that make the copper soft (annealed). Retry. Check the other surfaces to make sure they are clean.

That is what I do when using old copper washers. If the parts came from china, I might question the metalurgy since copper is not like gold.

The proper method to anneal copper is to quench it in water after heating.  Unlike steel where you let the part cool slowly.

I learned something today. And its only 8 am.

Off to read up on this.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) PowerDork
6/12/22 8:41 a.m.

Allright, I'm a couple of cups of coffee in on a lazy Sunday morning. Maybe I can make some sense.

Patrick, are you saying you have some of these calipers on your vehicles? Looking at my picture again, it does indeed appear I have the banjo fitting angled toward the caliper (away from the axle). I'll definitely try it the other way again, but I have a question: does it really matter. Most banjo fittings I have used were on motorcycles, and non directional. I figured (wrongly?) that as long as you had a copper washer on both sides, it would work. Again, I'll get out there and try some of these things shortly.

And yeah, I knew, but had forgotten that you were supposed to quench copper to anneal it properly. Good call, Triumph7.

APEowner
APEowner SuperDork
6/12/22 9:49 a.m.
wheelsmithy (Joe-with-an-L) said:

Allright, I'm a couple of cups of coffee in on a lazy Sunday morning. Maybe I can make some sense.

Patrick, are you saying you have some of these calipers on your vehicles? Looking at my picture again, it does indeed appear I have the banjo fitting angled toward the caliper (away from the axle). I'll definitely try it the other way again, but I have a question: does it really matter. Most banjo fittings I have used were on motorcycles, and non directional. I figured (wrongly?) that as long as you had a copper washer on both sides, it would work. Again, I'll get out there and try some of these things shortly.

And yeah, I knew, but had forgotten that you were supposed to quench copper to anneal it properly. Good call, Triumph7.

I'm obviously not Patrick but it looks like the fitting is angled so that the part the hose goes into is hitting the caliper preventing the bottom washer from compressing.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
6/12/22 10:14 a.m.

I am *a* patrick but not *that* patrick. I was not referring to the angle, I was referring to whether the tube is centered on the width where it comes off the block. Like, if it's not, perhaps it needs the offset to be away from the caliper.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) PowerDork
6/12/22 10:33 a.m.

All you Patricks are absolutely correct. Also APEowner, and pretty much everybody in this thread but meblush

See that little shoulder to the top of the picture? Yep, totally matters which way they go on.  In related news, my deteriorating eyesight may be a factor in this. 

Thanks all. Another rescue from idiocy by the brain trust.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) MegaDork
6/12/22 2:26 p.m.

I've had a plethora of reman calipers that were heavy-handed on the bead blast and it destroys the concentric rings.  I had a similar problem with a step van caliper and I couldn't find a replacement.  I fixed it by chucking up a forstner bit I didn't care about in the drill press (sideways so the shavings didn't go in the hole) and sorta polishing it, then I used a hole punch to make a punched circle where the rings used to be for the copper.

Annealing the copper never worked for me, but I can see how it would help.

wheelsmithy (Joe-with-an-L)
wheelsmithy (Joe-with-an-L) PowerDork
6/12/22 2:34 p.m.

I ended up mangling the copper washers, and having to get new ones from the FLAPS. Seems to be holding fine. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
6/12/22 2:41 p.m.

In reply to Curtis73 (Forum Supporter) :

Enough calipers are flat there that I have never felt bad about hitting rusty ones with a cookie and ending up with a flat surface.  As long as it is square with the threads it will be fine.

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