4 Wheel Disc Brake Conversion

[chrise1984]

Hello, I have an 84 Hurst and have converted to four wheel disc brakes. I am having trouble finding a master cylinder for four wheel disc, I thought I had a source, but it was the wrong fit. Any guidance would be appreciated!!!

 

[scoti]

Hello, I have an 84 Hurst and have converted to four wheel disc brakes. I am having trouble finding a master cylinder for four wheel disc, I thought I had a source, but it was the wrong fit. Any guidance would be appreciated!!!

1979 -81 Trans Am's were factory available w/4whl discs.

 

[ssn696]

You might consider one from an early 80s Riviera. You may also get away with swapping only the proportioning valve on the frame rail. Aftermarket or Riviera…

 

[57 Handyman]

Is finding a 4-wheel disc master cylinder necessary versus adding a 4-wheel disc proportioning valve? It would seem the proportioning valve is an adequate solution.

 

[scoti]

Is finding a 4-wheel disc master cylinder necessary versus adding a 4-wheel disc proportioning valve? It would seem the proportioning valve is an adequate solution.

Necessary? Not really. But, it's not a bad idea either for fluid volume.

Same thing w/the prop valve. Having the ability to dial in rear pressure is a very good tuning item to have when making changes like this.

 

[57 Handyman]

Scoti, so is there a difference in brake fluid volume/pressure between the 2- and 4-wheel disc master cylinders? Shortly, I plan to upgrade to disc bakes on my 87 El Camino which has an 87 GN 8.5" rear end. I purchased a 4-wheel disc proportioning valve from OPGI to support the conversion. It does NOT have any adjustment capability.

https://www.opgi.com/brake-systems/proportion-valves/brake-proportioning-valve-replacement/proportioning-valve-discdisc-brakes-1964-72-a-body-1978-88-ecmc-ch26776.html

Is this the correct part?

 

[scoti]

Scoti, so is there a difference in brake fluid volume/pressure between the 2- and 4-wheel disc master cylinders? Shortly, I plan to upgrade to disc bakes on my 87 El Camino which has an 87 GN 8.5" rear end. I purchased a 4-wheel disc proportioning valve from OPGI to support the conversion. It does NOT have any adjustment capability.

https://www.opgi.com/brake-systems/proportion-valves/brake-proportioning-valve-replacement/proportioning-valve-discdisc-brakes-1964-72-a-body-1978-88-ecmc-ch26776.html

Is this the correct part?

Disc brake caliper pistons move more fluid vs drum brake wheel cylinders. Different master cylinders (especially manual vs power) have different bore sizes which varies the pressure.

As far as the metering/prop valve, that's one of them that's available. I know I've read about issues w/one manufacturer over another so do your homework on any supplier.

When I do the Blazer/f-body rear disc swap on my g-body, I'll be utilizing an adjustable valve inline to the rears in addition to the factory style metering block. I typically run different F/R tire sizes so being able to adjust/compensate for the different heights is a good thing.

 

[57 Handyman]

Thanks. I may insert an adjustable valve also in the rear. Interestingly enough, I have installed 2000 Blazer front spindles and will install the disc brakes on the rear. Installation of rear calipers will be delayed due to requiring more engineering and modification in order to accommodate e-brake setup. Stay safe!

 

[ssn696]

Will you use the stock foot pedal or add a handbrake?

 

[abbey castro]

I have the S10 front and Camaro rear disks. Only changed the proportion valve for a disk /disk one. Have good brakes with no issues at all with good brake pedal feel and travel.