FE-FC Holden Discussion Forum

I finally got the brakes bled properly, but the rears still lock up.
I pulled the brake drum off, then the dust cover on the brake cylinder and put the calipers over the piston, this came to 22mm (7/8?). I have read else where that I probably need to be running 9/16 (14.3mm) rear cylinders which agrees with the Torana manual for a disc front end (All torana brakes).
The car goes to Dept of Trans for another rego inspection and I want to put this problem to bed. Will the smaller wheel cylinders stop the rears locking?
Can you get 9/16 cylinders for a HR diff?

Thanks in advance.

Not sure on the sizes but 7/8 sounds too big for use with a disc brake front end. The rears were always substantially smaller than the drum brake set up. I have standard HR rear wheel cylinders for disc brakes on mine with no problems and if I remember rightly I used a full set of rear brakes of a lc-lj torana on an old flyer I had years ago and they bolted(backing plates and all) straight up to the hr rear end and were basically the same brakes. I'm sure wheel cylinder sizes were same as the disc brake HR rears.
All this to one side I would say yes, smaller wheel cylinders will fix your problem.
You can buy a set of HR rear cylinders for a disc brake set up off the shelf at local brake shop and bolted them in. Problem solved I'm sure.
Someone may confirm sizes etc but by the sound of it your cylinders don't match a disc brake set up.

Thanks Addo, I put the diff together a long time before the car was drivable, but I am sure I researched and bought the right stuff.
Anyway, off to the brake store tomorrow and hopefully rego on Thursday  ;D

OK, I have the correct(?) size wheel cylinders.
Next problem.....
The large wheel cylinders currently on the car have a couple of push-rods that are used to activate the brakes. The new smaller wheel cylinders do not have these, I am guessing that the brake shoes are different between the two?
Is there a way to adapt the wheel cylinders? or do I have to go out and buy new shoes?
(http://i9.tinypic.com/300gqbm.jpg)

Had a thought, would it be OK to make up a little piece out of three bits of metal, the middle (red) one to fill the gap in the brake pad and the other two (one on each side) to locate the piece.
(http://i9.tinypic.com/44vv760.jpg)

Other than that someone suggested welding the pushrods to the brake cylinder  ???

Hi Stinky,

your guess was correct, the brake shoes are different between the two types of slave cylinder...instead of having a recess in the web for the "forked" push rod, the web protrudes to meet the short piston n the slave cylinder.

the idea of a small spacer to pad it out seems plausible, but given braking is often an emergency-type activity, I know I'd always be wondering if they were gonna be there when I "needed them".

I guess that's why I have a spare set of HR rear brake shoes sitting amongst my spares....I found out they were different AFTER I bought the smaller slaves too!!

cheers....Brad

What do the new cylinders have instead of pushrods? been a couple of years since I had mine apart, I'm going to whip a wheel off tomorrow and check it out. I'm sure they have rods. (could be wrong though).



Ok I must be wrong.
I'm still going to look!

Stinky,

The new shoes aren't that expensive.  I paid about $55 from Repco for 1st oversize over the counter about 2 years ago.

My car had been previously registered and driving round for years with the incorrect rear set up.

Keep the pins off the old set up though, just incase you ever need a drum set again.

Dave

Thanks Brad and Dave, I thought better of my "hare-brain" idea and got the right pads ($38 from my local Sprint Auto parts store  ;D )

I also remember the circumstances as to how all the wrong stuff was fitted up in the first place, bloody brake shops! They do good work on standard stuff, but throw them a wobbly like my car  ::)