I am completing a mini truck disc brake conversion on my ’72 FJ40 and have run into a problem. The problem is in the rear brakes. They don’t lock up:confused: . I changed the stock MC to a unit out of a ’83 Celica. That car should have had disc front and drum rear. I have a feeling that the problem lies in the lack of a residual valve for the rear. I checked the old Celica MC and could not find any residual valves. Could there have been a valve that was place “inline” to give the rear drums the necessary line pressure? If so, is there a way to put a residual valve “inline” to solve the problem. If all else fails, I can go back to the original MC and just remove the valve out of the front :D .

Randy <><
aka. webmaster
‘72 FJ40, stock F engine, LC 4 speed,
York, No-Slip(rear), Lock-Right(front),
Mini Disc Front, Saginaw P/S.

I run a mini truck master cylinder with no residual valve that I'm aware of. As long as the breaks are adjusted correctly, they work fine. Im not totally sure but I think there's not much differance between the Celica and the mini truck.

Any vehicle that had drums on either/both ends should have a residual valve. The high return spring resistance will force the fluid back into the master with out one.

You should still be able to lock them up without one, might take a few good pumps of the pedal to deliver enough volume/pressure.

I would verify that the brakes are in good shape and adjusted correctly. Thats my suggestion without seeing the vehicle.

If I pump it up 3-4 times it will lock up. In that time the front is already stopped. The difference betwee disc and drum is amazing. I did some more checking and the Celica did have the option of rear discs. Maybe I should just go ahead and do the rear discs? ;) This could work.

Hey LCowner,
Are you gonna be at Moonlight Madness?? If so stop by our camp. Look for the 4x4Him banner and my cruiser.http://4x4him.com/images/randy3.jpg

Originally posted by cruiser4randy
If I pump it up 3-4 times it will lock up.


This shows that it is in fact an adjustment problem. Adjust the rears and you will be fine.

Are you camping with Buzzard? I may do that.

Yes I will be with Buzzard and Momma Buzz. Drop by if you get a chance.

I adjusted the rear shoes so that they drag just a little bit. I tried it again and found that the braking is better but the draging has a very negitive effect on the No-Slip locker. It wants to lock and unlock repeatedly:( . I will take the advise posted here and at the other boards and work on it again today. More updates tonight.

Don't waste any more time on those rear drums. You are well on your way to the best set up now - just go ahead and do the rear disc swap. It's only about 200 bones and well worth the $$. You'll be glad you did - trust me!

My guess is that your rear brakes won't work correctly because the cruiser rear drum cylinders are larger and require more fluid than the celica ones.

Example of this was a friend who bought a '73 chev dually. The brakes were worn so he had the dealership replace them when he bought it. After picking it up he went to brake for the stopsign at the end of the block and went right through the intersection. Turns out that the wheel cylinders were replaced with ones that had a slightly larger bore and the MC was not pushing enough fluid to the back cylinders to make them lockup like they would with the smaller bore cylinders.

Well today I jumped in the truck and went for a good test drive. I didn't get a half mile from the house when I noticed the brakes were locking up. At first I thought it was the rear brakes but it turned out to be the fronts! I limped it home and switched out the MC back to the original for my '72. I did remove the residual valve from the front line. After bleeding the system, I again ventured out on the road. This time everything worked perfect. The moral of this story seems to be: Don't use a master cylinder from a '83 Celica! My thanks to all of you who responded.

Now a happy Cruiser again :)

Randy