Wheel Cyl Leaks???

[55 Fargo]

Hi all, I did notice in late fall, I seemed to have a rear wheel cyl leaking a bit of fluid when I pulled back the boot.

I have not repaired or replaced this yet, when the brakes were inspected nothing was leaking into the backing plate, so I did not even think of it.

I wonder is it possible to leak out some fluid and then stop or is it so slow that it has not built up enough to leak out of the boot on the cyl.

I am going to have a closer look later this week, will repair or replace as necessary...............Thanx Fred ps have driven the car alot since last fall, no brake problem detected

[Norm's Coupe]

Evidently the fluid is getting past the 0 ring on the piston. If it is leaking a little it won't be long before it drips out the boot, then destroys your shoes. I would either rebuild it now or replace it. Actually, I'd vote for replacing the cylinder altogether. I've never had rebuilt ones last that long.

That said. If you rebuild or replace only one cylinder and the rest are old, they are also weaker. Because the new or rebuilt one stops leaking when repaired or replaced, it throws more pressure to the other older, weaker ones and may cause them to leak too.

[curtiswyant]

Replace it.

[55 Fargo]

Most likely I will, I have had and others have had success with kits and rebuilding, but maybe this one is to far gone. I most likely will replace all of them, as I can buy them NOS locally, for a sweet deal, I then have new rubber installed............Fred

[oldmopar]

If you are going to replace all the wheel cylinders I would complete the job and rebuild or replace the mc, brakes hoses and lines. Then you also will be able to use silicone dot5 brake fluid if you want to I have used it in 3 cars with complete brake jobs and no complaints

Ed

[55 Fargo]

Hi, this has been done already profeesionally rebuilt MC , all new lines, hoses, shoes, rebuilt slave cyls, rebuilt ebrake band, new ebrake spring, all works well, there is no evidence of leaking right now, just once on one rear wheel cyl, when I pulled back the boot there was some brake fluid. That is enough to replace it. I have DOT 5 silicone brake fluid in my system already.

I am going to inspect everything very closely myself again before the driving season really begins up here, and will replace anything suspect. My big plan is to someday buy the ECI disc brake kit and dual MC, but right now my pockets are lean..................thanx Fred

[oldmopar]

Hi, this has been done already profeesionally rebuilt MC , all new lines, hoses, shoes, rebuilt slave cyls, rebuilt ebrake band, new ebrake spring, all works well, there is no evidence of leaking right now, just once on one rear wheel cyl, when I pulled back the boot there was some brake fluid. That is enough to replace it. I have DOT 5 silicone brake fluid in my system already.

I am going to inspect everything very closely myself again before the driving season really begins up here, and will replace anything suspect. My big plan is to someday buy the ECI disc brake kit and dual MC, but right now my pockets are lean..................thanx Fred

That should be good with all that work done if it keeps leaking I would just check that cylinder if it is clean I would try a rebuild kit or maybe hone it and rebuild

Ed

[James_Douglas]

I had 24 months ago, and several others in other clubs, have reported NEW drum brake cylinders failing within 18 months of replacement.

The quality of the castings and seals have been in question.

I now send all MC and wheel cylinders to Joe at Sierra Automotive and have them brass sleeved. I inspect very carefully all seals and assemble the units myself with brake assembly fluid.

Having a new cylinder fail on a hill here in San Francisco was not fun.

Don't trust the stuff in a box on a single MC system.

James

[RobertKB]

James, I believe you are right about the quality of a lot of the new stuff. I also think it is worthwhile sending out the old cylinders and having them sleeved with brass of stainless steel. I has White Post do my master cylinder in my '38 Chrysler years ago with brass and I then rebuilt it very carefully. No problems so far and you never need to worry about pitting. Resleeve is the way to go and is what I will do to all cylinders in the future. Kits are cheap.

[Norm's Coupe]

I bought new wheel cylinders for my coupe from Kanter about 4 or 5 years ago and have had no problems with them leaking. Did replace the front brakes with disc brakes, but not because the cylinders were leaking. The rears are still on the car.

[bob_amos]

Brakes... leaking fluid.... there is nothing to consider. ALWAYS, ALWAYS replace or rebuild any brake part that is suspect. Also, I recommend you look all the others over. and remember, replace cylinders in sets. Meaning a back cylinder leaking..replace both. A front leaking... replace all 4, if that is what you have or both if you only have one on each side. That is a standard of the industry. If leakage is found at all cylinders you might want to think about that master too... A contaminate may have been introduced into the system.

[55 Fargo]

Okay Bob, that makes total sense to me, what is the rationale to replace both sides up front if one wheel cyl is leaking in a front dual set-up.

I would think a vehicle that was being driven on a regular basis, and say one rear wheel cyl springs a leak, then it would be wise to replace both rears, as they would presumably both be worn or have the same age on there use.

But they were say both rebuilt or new, and one starts to leak what would be the rationale to replace both rears? I know it is not that expensive to replace the other rear cyl at the same time. Just a thought, I believe it is always wise to err on the side of caution, than be sorry.

I always check whats going on, I do not pull the drums every week, but I do watch the MC and lines as well as the backing plate, as a leaking wheel cyl won't take too long to pour out brake fluid...........Fred

[bob_amos]

We have found that older cylinders do not have the same response as the new ones. Upon applying the brakes there may, and probably will, be a pull to one side. Ya see, new cylinders will respond and apply the shoes right away while there may be a slight, or even large, delay for the older units to apply the shoes. This would cause a dangerous pull. I've been an auto tech. for over 40n years and we ALWAYS do both sides. While I worked for Chrysler dealers Chrysler Corp. would buy replacement of both sides under warrantee. Even when only one side was having a proble. Be it leakage or binding or what ever. And when the manufacturer will buy them both under warrantee, you have to know there is a sound reason. Safety is always first in my mind...

[55 Fargo]

Makes good sense to me, thanx Fred