Disk/drum brakes with disk/disk master

[Gunnibronco]

This is going to sound stupid.

I've been running a 99 Mustang GT hydroboost & master cylinder on disk/drums for YEARS. On both my stock width & full width axles.

I know this isn't exactly right. I think I've read I might be lacking rear brakes because there isn't a check valve or something that would keep the rear cylinders "pumped up" between uses. I think I even read it can cause the cylinder to retract & the rear brakes can fail completely.

Since I pulled my frame mounted rear brake line, and have drained the system of fluid, I'd like to fix this now. I hate bleeding brakes, and my hatred prevents me from modifying any part of the brake system, unless absolutely necessary. So now is the time.

Can someone tell me what I need to add to the system to get it right?

[phyler]

You are talking about the residual pressure valve. Most new masters don't have them even for drum/drum setups.

I am right there with you on the hatred of bleeding brakes. I have everything to do the rear swap to Explorer discs but haven't for that very reason.

[phyler]

Just realized you might be needing a proportion valve to adjust the bias as well. Not sure if you are locking up the rears before the fronts.

[Gunnibronco]

Just realized you might be needing a proportion valve to adjust the bias as well. Not sure if you are locking up the rears before the fronts.

Sounds like I might be ok. Thanks.

I have a proportion valve installed that I don't need (don't ask- part of the reason I hate bleeding brakes). I locked up the rears with the regular F150 calipers, but switching to T-bird calipers fixed that with no need for a proportioning valve.

[ZOSO]

drums require a 10psi residual valve to keep the cylinders from collapsing. disc's use 2psi or less. You can pick them up pretty cheap. http://www.summitracing.com/parts/wil-2 ... /overview/

Be forewarned that with this you will need the adjustable proportioning valve.

[Gunnibronco]

Thanks Rob,

I'll leave the prop valve in.

[cpldavis37]

This makes bleeding brakes easy.

[cpldavis37]

I think I got one for $25.

[Gunnibronco]

I used one of those when I bled the 69 I flipped. It did go pretty well, still finished the job the 'old fashioned way' (with a helper).

[Gunnibronco]

drums require a 10psi residual valve to keep the cylinders from collapsing. disc's use 2psi or less. You can pick them up pretty cheap. http://www.summitracing.com/parts/wil-2 ... /overview/

Be forewarned that with this you will need the adjustable proportioning valve.

Is it important where this is installed in the rear system? Between the master & prop valve or after prop valve?