4 wheel disc combination valve

[L92 OLDS]

I use a disk/disk Cadillac Seville combination valve on my car and bias is perfect. If you run out of options let me know. I believe I have a clean one that is ready to install. It’s a direct replacement for a G body and will connect to factory lines.

 

[81cutlass]

My new aftermarket disk/disk prop valve failed in the same way both of yours did when I tried it in 2017. The brass style aftermarket ones are direct swap overs to the factory G body cast iron Kelsey-hayes or Bendix supplied ones ( I forget what style the G body has but almost all the OEM valves are originally supplied by one of those two manufacturers)

Either the Bendix or Kelsey-hayes can be 'gutted' and converted to run disk/disk by removing some spring and ball, but the G body factory valve is the type that can't be converted. The aftermarket style is a clone of the type that can be converted. From what I gather it's just missing the drum pressure reducing parts that the disk/drum style has.

Potentially inline tube or other 'premium' distributors have some test that they pay for that makes them better than the elcheepo fleabay style but again, I haven't seen any evidence they are supplied by different manufacturers. The design is the same and volumes are low enough I highly doubt there is more that one oversees manufacturer.

If you are firm and want a replacement that will 100% swap an NOS ws6 f body part is probably your only shot.

"1978-81 FIREBIRD TRANS AM 4 WHEEL DISC BRAKE VALVE NEW GM NOS OLD STOCK 1257189 | eBay" https://www.ebay.com/itm/3627415265...d=link&campid=5335822911&toolid=20001&mkevt=1

 

[64nailhead]

Been down this trail once. Bought an aftermarket disc/disc and it felt the same as the factory setup with C5 front and Seville rears. Swapped back to the original disc/drum prop valve and couldn't tell the difference.

I have another car that I'm using the stock valve with oversized metric fronts (2.75") and Explorer rear discs and it works fine as well.


I believe the stock prop valve works well more than adequately for 90% of all setups until you get into varying tire sizes.

 

[Texas82GP]

I bought an NOS GM valve for my car. I already had a new aftermarket valve but heard too many bad things about them. My NOS valve came home from Jordan (the country). It wasn't cheap, but it's the real thing.