M38Cdn Refurbishment

[Barry Churcher]

Peter if you still have the old copper gaskets just reuse them. When installing new brake parts we never use the new washers as there are too many leaks. The old washers seem to be leak proof.
Cheers, Barry

[rob love]

There does not seem to be a correct torque for the new copper washers.I have tried them from loose to almost stripping the cylinder tight.



I got so frustrated trying to use new copper washers with silicone brake fluid, that I finally smeared the thinnest/lightest coat of silicone glue on them possible. That did the trick, but is not an approved method. My thought was silicone with silicone....what could go wrong?

[Peter Phillips]

Barry, unfortunately I think they're gone already, dang it! Never would've guessed that would be the preferred method than using new ones, interesting

Rob funny you mention that as I've tightened these beyond what I would normally do...and I've done a lot of brake work since 1984! I went with DOT 4 for this system as it's driven in dry conditions and parked in a climate controlled shop.

There's got to be a work around for shoddy copper gaskets? I've got a leak at the front axle brass tee, and at the 2 larger ones on the master cylinder banjo bolt. The rear tee and front wheel cylinders are good, weird?

[rob love]

Are you talking about inverted flare fittings at the wheel cylinder and brass T connections? In that case, too tight and the flares themselves either split or over-compress and lose their ability to seal. Are you trying to use sealing rings in those connections?

I can certainly understand leakage at the master cylinder copper gaskets. But usually flare fittings are pretty good to seal.



Personally, I like DOT4, especially for larger trucks or trucks pulling a load. I remember having my brake fluid boil off when towing a heavy load in to medicine hat. I walked to a local autoparts store, bought a pint of DOT4, put that in and didn't even have to bleed the brakes. That fluid lasted for another 10 years until I got rid of that truck.

[Wayne Hingley]

Looks great Pete. I guess with the price of copper going north of $4 USD we are seeing blends of other metals rather than pure copper washers for use in brake systems. I didn't know the new washers are junk.
I see the "supervisor's chair" in one of your photos. Its good the boss is providing over watch, so you don't get yourself in trouble.

[Tony Smith]

Originally Posted by Wayne Hingley

I guess with the price of copper going north of $4 USD we are seeing blends of other metals rather than pure copper washers for use in brake systems. I didn't know the new washers are junk.

I don't think the issue is the price of Copper, I think it comes down to the source of the washers, where they are produced, and that is what has seen the change in the alloy used.

Some searching at swapmeets, old hardware and plumbing suppliers, and even weekend home garage sales will quite often turn up NOS/vintage packets of washers (and nuts/bolts, etc) that are of far better quality than new items from even reputable retailers.

[Phil Waterman]

Hi Guys

First Peter excellent overhaul, restoration, or preventive maintenance program, definitely setting the Jeep up for another 50 years.

It would be interesting to check the hardness of NOS 1940s brake washers vs New 2020s washers. I suspect that the percentage of recycled copper is making the washers harder to the point where they no longer deform to seal well. At the same time has any one notice that new manufacturer brake cylinders the circular groves the washer are to fit against and deform to seal are not as sharp.

Jumping to old fix for washer and cylinders that doesn't seal. Clean a copper washer then heat and apply solder wipe off excess. I have even use this trick when only had a used washer to finish a brake job.

The suggestion to grab true NOS washers whenever you chance on them is a good one.

Cheers Phil