Brake mystery
 

I am working on a friends 29 Coupe. The brakes were converted to juice brakes many years ago. My problem is adjusting the front brakes. If I adjust the brakes so the wheels spins with little resistance, it should work but if you step on the brakes the brakes wont release. I replaced everything with the rebuild kit from Macs. Is this a china wheel cylinder problem?

Re: Brake mystery
 

. Is this a china wheel cylinder problem?[/QUOTE]
It's possible. Some repop cylinders had the fluid return hole drilled in the wrong spot and the rubber would stop atop it - not allowing the fluid to return.

I might suggest when this happens, go quickly to one wheel (at a time) and loosen the hose at the cylinder a bit. If the pedal becomes "friendly" right away, you know the issue is in that cylinder. Repeat this for the other side.

From your post, might it fair to assume the back brakes are releasing?
If all of the brakes are locking up, I'd check the rod adjustment at the master cylinder. If the stroke is too long, the fluid will not be allowed to return to the master.

Re: Brake mystery
 

I had this happen on our 38 conv, turned out the rod in the master cylinder, needed adjusted, every time I used the brakes it keep building up pressure, wasn't letting floid go back to mc, adjusted rod all ok

Re: Brake mystery
 

Do you have a dual master cyl , where its it placed , under car or firewall, and do you ha a proportion valve or residual valve ?

Re: Brake mystery
 

Thanks, I will use your suggestion. This car was restored to go to a museum in 2002. Great looking car but they did not restore anything mechanical. Just cleaned up and made to look good. It has been a challenge.

Re: Brake mystery
 

Single master cylinder.

Re: Brake mystery
 

Start by making sure that the return spring returns the pedal COMPLETELY. If good to go, then you should insure that there is FREE-PLAY at the pedal. Free-play is a slight movement of pedal (perhaps 3/4" or so) of the pedal before meeting the resistance of the rod actually pushing on the M/C piston. There MUST be a space of 1/16" or so between the pushrod and the M/C's piston when the pedal is fully retracted by the return spring. If the piston does not FULLY retract, your symptoms will result. DD

Re: Brake mystery
 

Haven't there been problems with the inside of the hoses collapsing and acting like check valves?

Re: Brake mystery
 

I can never remember this happening to any of my old cars but it did it on my 20 year old daily driver. I had a sticking caliber which I replaced only to have the new one do the same thing. I pulled the brake hose and could not blow through it.i cut it apart where there was a metal sleeve over it and it was collasped where some rust swelled the metal sleeve.