Hi Joe, quick question. I got the car finished and the brakes work but not like they should. I bled them very good with my vacuum pump after installing that proportioning valve. I had the shop I took the car to for the alignment (I completely rebuilt the suspension and steering) and had them look at the brake issue.

They told me that there are now two proportioning valves on the car including the one I installed after the disc conversion. The only other 'valves' I saw in the stock brake lines where the blocks that take the brake lines from one to two to go to each corner.

Do you happen to know if there is a factory proportioning valve on the original all drum brakes?

I am going to pick the Cutty up now and plan to have them show me exactly what they are talking about but thought I'd ask here as well.

Thanks in advance!

 

Get pictures !!!!!

 

Hi Ralph, I really don't have anything to get pics of other than the proportioning valve I installed (I posted a pic of it not installed earlier in this thread.)

The only things I saw on the car from factory were the two distribution blocks, and I know those aren't proportioning valves. If I can get a pic of what the shop is talking about then I will post that. Was there something more specific you'd like to see?

Thanks guys!

 

Have them take cell phone pics and send them to you.

 

There are no proportioning valves on any A-body with four wheel drum brakes, period. In fact, the only Olds that I'm aware of that ever used a prop valve on a four wheel drum car is the early Toronados due to the high front weight bias.

If you have the new brass combo valve as shown above in Post #21, that's the only thing that should be in the system. It replaces the old distribution block used with the drum brakes, however that distribution block is not a "proportioning valve". Any shop that thinks it is has no clue about GM brakes and should not be touching your car.

 

Thanks Joe, that's exactly what I thought, even the shop manual supports that. It was Big O and it just went in for an alignment and I asked them to give the brakes a once over.

I have a very low pedal, brakes grab well 1/2 way down but if I apply more pedal, I then go to the floor with brake fade. Either way it sounds like I need to take that front distribution block out completely. I had one guy (who builds a lot of cars) advise me that it was not necessary to run two dedicated lines from the front calipers because the distribution block was in place. Sounded logical, so I capped one side on the P valve and ran the factory single line from the dist. block to the other port on the P valve. Apparently, this was bad advice?

I really appreciate the help!

 

I moved your question to its own thread instead of hijacking another.

 

It was unnecessary work. The reality is that the way you've described it shouldn't fundamentally change how the brakes work, however the added complexity provides many pockets for air to remain trapped in the brake circuit.