[jack]

Need info on what to get and where?

I got a 71 cutlass disk brake set up off a junker and had it put on my 65 Chevelle Malibus front- drums in the rear.
I have power disk brakes (dual res.)

My mechanic says that my proportioning valve doesn't work.
Olds doesn't make them anymore, and all the after market dealers around here don't carry them.

Do I need to get
an adjustable proportioning valve set up
or
one of those combination valves that has a metering to the front plus proportioning and residual to the rear???

Thanks,
Jack

[ChrisP]

I share your pain. I put '70 A-body power discs on my '67 Malibu. Do you have a separate proportioning valve than the distribution block? Mine hasn't gone out yet but I want to replace it for reliability reasons. If anyone can help please do.
Thanx

[66 bowtie]

well i think that an adjustable one would work. It might even be better so you can set how the brakes react asto how much pressure on front and back. Have you went to a speed shop or something and asked them what they think? maybe they can get one

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OWNER OF 66 CHEVELLE MALIBU

Check out page dedicated to resto of my chevelle. still being made.
www.geocities.com/MotorCity/Shop/9801/


Canadian Classics Chevelles and Beaumonts #393

[JWagner]

Ow do you know that your valve is bad?? I would like to know of the good way to test these. My experience has been that if you are locking the rear wheels, the valve is the second choice with grease in the rear brakes being the first choice. And , you may hit the salvage yards and get a valve from a later GM car which will probably solve your problem if you want a drop-in part. The adjustable still sounds like a good deal if your rear brakes are working properly.

[ChrisP]

66 bowtie
I've checked with local speed shops and the say to get an adj. prop. valve. Of course they try to sell you anything and everything they can. The problem is that one speed shop said to place it in the front lines where the proportioning valve is and the other said that when the proportioning valve goes bad to bypass it and place the adj. valve in the rear brake line.
I'm just getting confused.

[jack]

Guys,

My mechanic buddy tested it for me, I'll ask how he tested it. I'm pretty lost when it comes to brakes and pressures .
He discovered the problem when he was doing the brake bleed on the conversion install.
My car doesn't run yet.

Since I couldn't find a Cutless I bought an adjustable proportioning valve today from Jegs. Totally Stainless makes it.
With cost and all, it goes about $50.00.

The sales guy runs one in his car, and it's so close to him, that he can easily adjust it when he's at the track .
Must be a different setting for strip vs street?? With line locks and all the different setups they use??

He said it would work fine for me.
It just takes a little adjusting to get the right feel for the brakes.

I'm sure Bob Tiley can answer our questions, or someone else with his experience??.
See ya,
Jack

[Bob Tiley]

First off, the Cutlass or a Chevelle does not have a proportioning valve from the factory, so how could it be bad if it doesn't have one?
The 69 and 70 GM cars had a seperate Metering valve, but this does not do any proportioning to the rear brakes, it is mounted on the front brakes and delays the front brakes a little until the rears can kick in (drums are slower reacting).

The adjustable proportiong valve is a good idea to add anyway, you need to put it in the rear brake line after the distribution block. You can either mount it on the frame below the drivers door, or at the rear axle. You will have to trey different settings to get all 4 wheels to lock at the same time.

If your wheels are locking up you may need to pressure bleed the system, There may still be air in some of the lines.

[jack]

Bob, I knew you would know.
I appreciate your input.
I went by what the mechanic called it.
Maybe it's that metering valve that he's calling a proprotioning valve.
He said he tested it and it only went one way???

I like the idea of getting that proportioning valve, and attaching it near the drivers door on the frame.
Thanks, Jack

[RatPowr]

Why cant you put the Adj. Proportioning valve inline right after the line exits the rear-brake line of the master cylinder? What will mounting it after the Dist. BLock change?

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66 Big-Block Chevelle Houston, TX ACES#3321

[ChrisP]

Hey Bob,
Sorry about the confusion. The metering valve is what I was calling a pproportioning valve. The metering valve on my Malibu is starting to leak around the little rubber boot on the end and I was just wondering if an adjustable prop. valve could replace this. I've been told they don't make these metering valves anymore. If I change to a '71-'72 propotioning valve I'd have to change all my line fittings.
What can I do short of redoing the whole system?

Chris, and adj prop valve goes in the back brake lines. The leaky metering valve you've got is in the front line. Master Power Brakes can rebuild it for you, but probably won't be too inexpensive. But it's an option.

[Bob Tiley]

Rat,
If you put the adjustable prop. valve right after the master cylinder every time you hit the brakes the brake light in the dash will come on. The distribution block has a switch in it to sense different pressure front verses back that would indicate a leak in the brake system. It would really work but you would have to unplug the warning light. If you put the new valve after the distribution block the warning light still works as designed.

[RatPowr]

Ahhhhh...what a releif! I had already put mine right after the master cylinder when I read that post! I dont have the light wired up or anything, so I though maybe you meant it wouldnt work period or something! Thanks for the info.

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66 Big-Block Chevelle Houston, TX ACES#3321

[eduardo69chevelle]

My 69 Chevelle has had the disc brake swap to replace the drums and has power assist. At this point I have completed the mechanical part of the job and am ready to do the plumming, but the discussions about the metering valve now have me puzzled. As I understand it, the master cylinder feeds the distribution block and then there should be a proportioning valve in the line to the rear brakes to allow adjustment of pressures to balance the braking. Does the metering valve exist on the original setup and is it required because I don't think my car has one. Some people use the term combination valve, but does this apply to the 69?

[69SSRat]

there should be a metering block on the frame but there is a proportioning valve just behind or below MC