plain old (stock) drum-brake wheel-cylinder observation

[rpoL98]

had a leaking rear wheel brake cylinder (massive leak), so had to replace. noticed that the bleeder port is BELOW the inlet, thinking that with that layout, there's no way to get all the air out of the cylinder. isn't the bleeder valve supposed to be at the HIGHEST point of the working volume: fluid--down, air--up?

it seems to me with this layout (design), incoming fluid will dribble into the cylinder, fill up the bottom third of the cylinder, and then go out the bleeder port. the remaining air volume that's above the bleeder port stays?

almost seems like you'd have to "bench-bleed" the wheel cylinder before installation...

just wondering.

 

[just plain john]

Obvious question, are you sure you don't have it inverted? Like you say, air can't escape as illustrated.

 

[charlief1]

You've got it mounted upside down.

 

[87gninpa]

Yup, just did mine a few weeks ago, bleeder is at the top...

 

[84 Sleeper]

Looks like you just have to flip it bleeder should be on the top

 

[rpoL98]

yikes! OMFG! how da hell did I miss that!

I'm the idiot... thanks!

good thing the car's still up on jackstands, was just getting ready to do the other side.

whew! that was a close call.

thanks all!

 

[charlief1]

LMFAO! Thanks for that after all the weather here today.

 

[Turbo85]

How did you get the spring that goes over the wheel cylinder installed. I am putting new rear wheel cylinders on and I am having a terrible time with it. Does it need a special tool or what. Thanks very much.

 

[charlief1]

Spring that goes over the wheel cylinder? Are you talking about the spring that goes from the shoe to the anchor at the top of the backing plate?

 

[rpoL98]

if you're talking about the white one in the pic above, although it looks like a spring, that's not a spring. you have to treat that one as sort of a "bracket" (made on the cheap), has to be in place before the spring is hooked to it. the 2 shoe-return springs, grayish in the pic above, are hooked on using "brake pliers", tool for working on drum brakes.

 

[novaderrik]

How did you get the spring that goes over the wheel cylinder installed. I am putting new rear wheel cylinders on and I am having a terrible time with it. Does it need a special tool or what. Thanks very much.

putting drum brakes together is a 2 minute deal per side if you just buy a couple of tools and get a little practice- the big brake pliers that is actually like 5 tools in one, and the tool that looks like a screwdriver handle that you use to put the shoe retainers on. you just gotta figure out which part of the pliers to use for what and everything kinda falls together.

 

[rpoL98]

i thought i might as well post "right-side up" pics, FWIW...

 

[87gninpa]

How did you get the spring that goes over the wheel cylinder installed. I am putting new rear wheel cylinders on and I am having a terrible time with it. Does it need a special tool or what. Thanks very much.

If you're talking about the large, circular retaining clip on the back that holds the cylinder in place, just put a large socket over it (forget the size at the moment) and give it a good tap, should pop right in.

 

[rpoL98]

for the circular retaining clip, put a piece of wood between the axle flange and the wheel cylinder, to hold it in place on the front while you finagle with the clip on the back.

 

[Turbo85]

Thanks for all the info on the retainer clip that goes on the back of the wheel cylinder. Helps alot. Another stupid question is what is the easy way to take that retainer clip off the old wheel cylinder?

 

[charlief1]

I have a pick that I use just for this. Get the pick on the edge of the retainer which holds the cylinder in and use a hammer do drive it in until it bottoms. The you have to bend the ears back to release it. It's a total PITA I know but that's why I changed over to rear discs.

 

[Turbo85]

Thanks again. Tomorrow is the day

 

[rpoL98]

Buick service manual says:
"remove wheel cylinder using J29839 Retainer Remover or two awls." I think the 2 awls method applies to most, worked for me.
"insert awls into access slots between wheel cylinder pilot and retainer locking tabs.
bend both tabs away simultaneously."

to install:
"position wheel cylinder assembly and hold in place with wooden block between cylinder and axle flange.
new retainer over wheel cylinder abutement using a 1-1/8 inch 12-point socket and socket extension."

i'm sure somebody from the magnificent Pacific Northwest will chime in about using 2 owls... sorry, couldn't resist.

pic in the manual shows that J29839 looks like some kind of a knob-adjustable lockring-type expanding tool. mebbe they shoulda assigned a Kent-Moore J-number to the wooden block.

 

[Turbo85]

Thanks to all, the brake job went kinda smooth. Those pesky clips holding the wheel cylinders didn't give it up easily. Started about 10:00 and road testing about 2:00. Thanks again, this form rocks. Lynno