Rear brakes - giving up on drums….

[jeffncs]

Many of you have offered advice and things to check on my dragging brakes. I give up on them. I’m buying a disc brake kit. Budget is $700 for the brake kit.

Details:
I have no idea which rear is under this truck so the kit will have to be adaptable to the different backing plate bolt patterns.
Welding brackets onto the rear isn’t an issue
Truck has 77 front discs
Vacuum boosted with the 77 master cylinder and disc-drum distribution block.

Questions ….
Which kit do you recommend? Most big vendors offer a kit which will work on any Bronco rear.
Do I need to swap the master cylinder to a disc-disc?
Do I need to swap the distribution block?

Thanks!

 

[Yeller]

Here’s my preferred kit from Quick Performance

 

[fordguy]

Jeff, did you keep any explorer disc brakes?

 

[widowmaker77]

Here’s my preferred kit from Quick Performance

I’ve looked at this kit myself. I have question about it maybe you can answer? There’s two types of nine inch rears you can select from a big bearing Torino style or a small bearing. It’s my understanding the Torino style was a medium duty nine inch offered in 75 . I have a 77 style, how would I order this kit for mine?

 

[ntsqd]

In the case of rear disc brakes bigger is NOT better (unless you're rolling on 40's). Yeller's link is the kit that I'd suggest for almost everyone.

Can look up the backing plate bolt pattern for all of the Ford bearing housings. Do that and then measure yours to figure out what you've got.

 

[jeffncs]

Jeff, did you keep any explorer disc brakes?

No. I was supposed to get another explorer last weekend but it fell through. Always looking though!

 

[jeffncs]

Here’s my preferred kit from Quick Performance

That’s a great kit and price! thanks @Yeller . I’m going to add some extra parts brake lines, e-brake cables…. They’ll also work well for the mustang 9” rear too!

Do I need to change the m/c or distribution block?

thanks again!

 

[joshua]

That’s a great kit and price! thanks @Yeller . I’m going to add some extra parts brake lines, e-brake cables…. They’ll also work well for the mustang 9” rear too!

Do I need to change the m/c or distribution block?

thanks again!

I’m pretty sure it’s just the proportioning valve

 

[DirtDonk]

You can initially use your existing master cylinder. Just make sure that the rear circuit (front reservoir usually) does not have a residual pressure check valve.
Most don't anymore, but if it's an older master, or just one that happened to get one installed, it's worth checking for.
Without a check valve, the fact that it's got a smaller reservoir is not an issue. The size is just to compensate for wear and the extra fluid needed as disc pads wear. Not an issue with new brakes.
But eventually, it would be a good idea to get a master with dual reservoirs that are larger.
If your pedal feel is good now, then adding rear discs can still give you a good pedal, as long as the caliper pistons are not so large as to need more fluid flow than the master is putting out (due to smaller piston size).
Don't know about the rear kit in question, but it sounds like others are using it, so they can comment on the pedal feel.

Regarding the "distribution block" though, what is it that you have? An actual proportioning/combination valve? Or is the original pressure differential valve still in place.
With a proportioning valve, you can still try it to see how it effects the use of the rear brakes. It's not "correct" to use it, but I can't say that it won't work. Or that it will make the brake function not acceptable.
If it's one of the standard type (such as a PV-1) you can get a disc-disc version that should theoretically replace the existing one with no adaptation. Or you could replace it all with a manually adjustable one.
Not sure just what the difference (if any) there is in the proportioning section. The main difference between a disc/drum and a disc/disc aftermarket valve is the elimination of the front delay/metering valve thingy. That's the nipple thingy sticking out of the front.
You should be able to at least use your existing one for initial tests to see how you like the rear.

And if the rear still drags, then you'll know that it was something else!

Paul

 

[Yeller]

Master cylinder, probably not, combination valve, maybe. I didn’t follow your brake thread, don’t know if you changed that all ready.

I’m going to get some flak for this and it isn’t the solution people want to hear for fear of change I guess. Non of my custom builds use a combination valve, and none have a brake warning light tied to the hydraulic system. I have one with the typical GM disc swap running this kit, has nothing from the master cylinder to the calipers, no valves of any kind and it stops absolutely perfect, brake bias is on the money, rear brakes apply first and do not lock up first, it’s perfect. In a bronco it may need an adjustable bias valve, it may not, but that kit gets the mechanical bias just about perfect.

 

[ntsqd]

There is no one correct answer, there are just the more commonly correct answers.

Usually a proportioning valve is needed, but not always. I call it a "Natural Bias" but ("mechanical bias" works) when the brake bias hits that magic spot where a p-valve isn't needed and the brakes behave as they should. I'd rather not use a p-valve if I don't need to, but it's pretty rare to get a system that doesn't need one (discounting the balance bar dual M/C's set-up - which is a nightmare unto itself!). One way to be sure to need one is to use one of those kits with weld-on brackets for the GM parking brake calipers. The pistons in those are much too large to work well with the common 1/2 ton front calipers.

 

[jeffncs]

My current setup has a stock style, rebuilt master cylinder designed for the 77 power disc brake arrangement. I can’t say if it has a check valve or not.

The distribution block is also a more modern unit. From memory, it’s a PV-2 for disc-drum. I may swap this to a PV-4 to eliminate it immediately from the equation prior to bleeding the system.

Thanks for the help!