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subzali
02-03-2008, 03:31 PM
What does one do when the rear brakes (drum) lock up before the fronts? '77 FJ40, dual master cylinder with FJ60 booster; I replaced the wheel cylinders and booster, bled the brakes (front and rear) a couple times, I think my rear cylinders are pretty well adjusted, though there is still more pedal travel than I would like, but they're just about dragging on the drums, so that's where they need to be. Pedal freeplay is okay.

Another thing I noticed when comparing the '73 and '72 front wheel cylinders to my '77 rear wheel cylinders - '77 rears have a 7/8 stamped on them and '72 & '73 fronts have 1 1/4 stamped on them - what does this designate? I'm assuming the older versions would have more stopping power (I don't think they were power brakes then), but if that number is the size of the piston then wouldn't a larger piston have less stopping power?

Any enlightenment?

nuclearlemon
02-03-2008, 03:45 PM
do you have a proportioning valve? is it adjustable?

no clue on the designations, i'd guess piston size also. 72/73 would be boosted.

subzali
02-03-2008, 04:22 PM
I don't read anything about a proportioning valve in Haynes or FSM, so I don't know...

The only thing that bothers me about the stamped numbers is that Toyota is metric sizes...

Rzeppa
02-04-2008, 06:48 PM
I posted up on the LCML in reply; the cylinders are much larger and powerful!

nuclearlemon
02-04-2008, 07:34 PM
I don't read anything about a proportioning valve in Haynes or FSM, so I don't know...

The only thing that bothers me about the stamped numbers is that Toyota is metric sizes...
if it's stock, it's inline, right by the master cylinder, bolted to the booster, iirc.

pretty much necessary to run discs/drums. the drums have to keep some pressure in order to engage promptly, the discs do not, so the proportioning valve allows that difference.