Wheel Cylinder Mystery

[ggdad1951]

Leaking at the fitting or inside?  two cyl per wheel or one?  single cyl per wheel, you can try switching the rubber cups from one side of the cyl to the other and recheck.  That'll tell you if it's the cyl or the cups.  It only takes a small flat spot, nick or rough spot on the rubber for it to leak or a score mark on the cyl.

change that to a TINY/INFITESIMALLY SMALL

[55 Fargo]

Leaking at the fitting or inside?  two cyl per wheel or one?  single cyl per wheel, you can try switching the rubber cups from one side of the cyl to the other and recheck.  That'll tell you if it's the cyl or the cups.  It only takes a small flat spot, nick or rough spot on the rubber for it to leak or a score mark on the cyl.

This is left rear wheel cyl, modern 1988 10 inch brakes 8 1/4 diff, I cyl. The leak is from the cylinder and not the fitting.

Funny thing is it is leaking the same side of the cylinder as the old cylinder. Could it be a problem with the pins,shoes or drum clearance. The shoes and hardware are new, the drums were machined, but were still in spec...thanx 

[Dave72dt]

It's the rubber behind the piston in the cyl or the cylinder itself.

[55 Fargo]

1 other thing Dave, the brake pedal seems awfully hard, and always has, could I also have  1 or other wheel cyls locked up? I wonder

[Dave72dt]

I've found manual brakes of the era to feel harder than the modern assisted systems.  It's possible but you should notice the truck pulling to one side  when applying brakes.  You do have a bit of free play in the pedal?  If the piston in the master doesn't or can't come all the way back, it blocks off the return hole in the master.

[Plymouthy Adams]

Fred..chage the right to the left and see if it follows the cylinder...

[55 Fargo]

Fred..chage the right to the left and see if it follows the cylinder...

Hi Tim, took it back to Local Jobber, and got another, that leak solved.

I bled brakes with 1 man brake bleeder, then lost pedal completely, this MC is not very good. I have the pedal back after pumping several times, its soft, probably more air in system, and no Helpers today for further bleeding.

With MC right full of fluid, how could I lose the pedal completely? the cup in the MC must be garbage, feel a sticking spot down low on the pedal while bleeding and pumping pedal back to life.

I am going to get another MC, and get things right, I hope..........

[Plymouthy Adams]

if the pedal went to the floor while bleeding..could be the piston stuck temporary in the master in the compressed position....and only the mechanical aspect of the brake returned to upright position..next compression could have freed the internals...sounds like time to inspect that MC real close..

[55 Fargo]

Yes will be doing this very soon, not sure which company I will get to re-sleeve this baby.

I really wonder what later model dual MC, might be a fairly simple retrofit? Any Ideas?.......

[55 Fargo]

Update;

Bled all brakes, with Wife's help, might be still some air but pushed out lots of fluid.

2nd new wheel cyl, is not leaking, once I bled all brakes  master cyl is not leaking either, at least i cannot see or feel anything, "touch wood".

This has Me scratching my head, and will still be pulling MC in warmer weather. Anybody else ever have this happen?

[ggdad1951]

Yep as I said earlier I swspped the wc out, bled yhe system and the problrms went away. Glad to hear it all worked out!