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Rear wheel cylinders over extending ??WHY?? Making a mess fluid everywhere!!!

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Jeffsbj8 said:
When I bought the car the rear shoes were removed along with cylinders and parking brake adjusters.
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Don't know if this is a clue. Previous owner must have been having rear brake problems as well. Did you reconnect the parking brake rods? I'm wondering if the parking brake levers in the cylinders were fully extended could they cause the piston to travel too far when you pump the brakes?

Also another thought. I bought some new rear shoes and the lining thickness of the new ones was noticeably thinner than the original ones. Might be something to check.
 
I'm having a hard time visualizing this... If you adjust the brake shoes so that they drag on the drum, I can't see how there would be enough movement in the shoes to allow the piston to travel far enough to pop out. At least not with a stock wheel cylinder.

Keith
 
Yes the parking brake rods were not hooked up but after brake job they were.As far as piston travel it moves enought to pop the sealing rubber on piston. Even if the brakes were not adjusted properly I can not see how the manufacture could design the pistons to over extend.These are the cylinders made in Taiwan. Has anyone purchased inferior cylinders? thanks so much
 
On Rick's thought, here is a shot of my brake cylinder. Note where the parking brake lever rides between the piston and the shoe, well, if the shoe was there to the left of the parking brake lever.
rear brake cylinder.jpg
 
Are the pistons in the cylinders back to front... I'm totally stumped as to how the pistons can travel about an inch without the shoes contacting the drums. They shouldn't be able to travel more than about 1/4" even if badly adjusted.

Can you take a pic and post it?
 
Jedi I will have to get a pic tomorrow.Are you saying I may have the wheel cylinders on backwards? Seems to me they only can go on one way , but I stand to be corrected .. thanks
 
Jeffsbj8 said:
Jedi I will have to get a pic tomorrow.Are you saying I may have the wheel cylinders on backwards? Seems to me they only can go on one way , but I stand to be corrected .. thanks
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Running out of ideas as to what it could be. The cylinders can only go on the backing plates one way but it could be possible to put the pistons down the holes in the cylinders upside down so the seal is at the top rather than at the bottom of the bores. There should be a slot in the top of the piston as in Greg's pic above.

When you put the pistons back in, how far do you have to push them back down the holes? Does the rubber-seal end of the piston go down the hole first?

Andy.
 
Yes they are brand new cylinders with the slot in the piston touching the shoe . The travel of the piston seems to be less than an inch and the piston seal is at the base of piston or you could say it would be first to enter the cylinder.Andy I am running out of ideas too. I am wondering if the travel of the piston in wheel cylinder is enough or if the piston seal is positioned correctly.I wish Lockheed was still around !!! I will keep plugging along you guys really have many great suggestions , keep them coming, thanks some more.
 
Yes I am just before ordering new kits for the old cylinders and trying them. I did have a Taiwain master cylinder , for same car that they forgot to thread one of the female hydraulic fittings.
 
Jeffsbj8 said:
Yes I have the drums on and brakes are adjusted . After this is done I simply pump the brakes simulating a stop , while on jack stands and the piston overextends making a mess.
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Sounds like you have the wrong shoes to me?????
 
After thinking a bit more about it, I reckon the wheel cylinder rubber seals are probably fitted onto the pistons upside down. They'll hold fluid fine while bleeding and then leak when the pressure goes on. Simple fix hopefully.
 
Hello Jeff, At this stage maybe its best if you post some clear pictures of what you have going on there! Then someone may I.D your problem! Did you look at the picture of my BN4 brakes i posted for your reference?
 
Could you guys send me an actual picture of your rear brakes? I'm running out of ideas and I'm wondering if I just made some little mistake. Thank you all for your input! Thanks, Jeff
 
don't want tp sound like a know it all but if you have everything on right tje piston can't move that far as to be pushed out ,make sure you have the right parts and that its a bj8 rear end ,you have to post some pics or your not going to get too much help
 
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