Well, after doing the swap to rear discs on my ae92 SR5.. and not changing the metering block to the GT-S block, I seem to be having a few brake issues.. Not sure if it is air in the lines.. or what.
But I was talking to an auto racer mechanic and he was telling me about proportioning valves to fine tune the brake system.
I was wondering if anyone here had some advice or words to say on proportioning valves and where I can get them for a good price, also what a good brand would be.
Yeah, drum brakes have a small amount of brake pressure constantly applied to them. Obviously this is no good if you switch to a disc brake.
So you can use a proportioning valve to remove the constant pressure that's going to the rear brakes. Problem solved
^that's part of it because drums have springs that pull the shoes back in, they need to hold some pressure in the line to keep the shoes from pulling to far from the drums. In addition, drums use less pressure than discs do. So not only do you need to remove the residual valve in the rear line, you need to readjust how much pressure it gets so that you have maximum braking.
A proportioning valve lets you limit how much pressure you get in the line you put the valve in. You can get one from a company like Wilwood(sp?)or for about 1/2 the price you can get a Mopar proportioning valve made by Wilwood.
__________________
Bob Raby
Santa Cruz, CA
'88 Alltrac (broken) FOR SALE
'87 4x4 Toy Truck SOLD
'90 4Runner (3.4 swap, CA certified legal with K&N intake, modified thermal coated headers, 2.5" exhaust, and almost as fast as a stock 3rd gen ) SOLD
I dunno. Might be easier to just use the valving out of the donor car.
__________________
Bob Raby
Santa Cruz, CA
'88 Alltrac (broken) FOR SALE
'87 4x4 Toy Truck SOLD
'90 4Runner (3.4 swap, CA certified legal with K&N intake, modified thermal coated headers, 2.5" exhaust, and almost as fast as a stock 3rd gen ) SOLD
Actually a proportioning valve limits braking pressure to the rear during HARD stops.
The METERING valve delays front brake operation until the rear brake spring pressure is overcome during LIGHT stopping.
The RESIDUAL PRESSURE CHECK VALVE would hold presure (10 psi) in a 4 wheel DRUM brake system to prevent wheel cylinder cup flare and leakage. Also used in applications where master cylinder is below the calipers/wheel cyls, mostly in custom hot rods and dragsters (3 psi)
A combination valve has METERING, PROPORTIONING and PRESSURE DIFFERENTIAL SWITCH (idiot light)
Now, exactly what sort of issues are you having so I can direct you to the proper replacement pieces parts
And YES, I DO teach this shit for a living
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ASE Undercar Specialist, UTI PHX automotive instructor driving a 1988 ST162, 3SGE, 5 speed. AFM mod and 15 degrees of timing on a otherwise stock vehicle (so far)
Well, I was close....
Now on a front disc, rear drum set up, isn't there still a residual valve for the rears?
__________________
Bob Raby
Santa Cruz, CA
'88 Alltrac (broken) FOR SALE
'87 4x4 Toy Truck SOLD
'90 4Runner (3.4 swap, CA certified legal with K&N intake, modified thermal coated headers, 2.5" exhaust, and almost as fast as a stock 3rd gen ) SOLD
Originally posted by alltrac165 Well, I was close....
Now on a front disc, rear drum set up, isn't there still a residual valve for the rears?
NO, not unless it originally had 4 wheel drum brakes
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ASE Undercar Specialist, UTI PHX automotive instructor driving a 1988 ST162, 3SGE, 5 speed. AFM mod and 15 degrees of timing on a otherwise stock vehicle (so far)
Hmm, wierd. There's no problem with the rear cup flare, leakage on a front disc/rear drum? I don't get it. Thanks, though.
__________________
Bob Raby
Santa Cruz, CA
'88 Alltrac (broken) FOR SALE
'87 4x4 Toy Truck SOLD
'90 4Runner (3.4 swap, CA certified legal with K&N intake, modified thermal coated headers, 2.5" exhaust, and almost as fast as a stock 3rd gen ) SOLD
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