disc brakes

[Jim100]

If one converts to disc brakes is it possible to not use a power brake booster?
jim

[jeffc57]

not a good idea to do it, that is why almost all disc brakes have power assisted units

[swptln]

It can be done. Very common with guys building street rods to run just the manual brakes. Much simpler install and if your running a bigger cam in your motor, etc. you don't have deal with low vacuum issues and putting vacuum reservoirs, etc.

[my5thmopar]

Yes. Manual disk brakes work great. You have to have the correct size master. I was using manual before I added a power booster. I may even go back to get that firmer brake feel. If you don’t have leg issues I say stick with manual. Contact Dr Diff, Cass will have everything you need for the rear. I don’t think he has front stuff but, you can ask. I’m using an older CPP on front. I wish I went with Dr Diff for the rear but, oh well. I’m still working the bugs out with the rightstuff. Craig

[712edf]

I ran manual brakes (and steering too) on a 78 W200 club cab that had Dana 60F with disks. No issues, just required more muscle.

Bucky

[Jim100]

Thanks for the feedback. Good to know it can be done.
jim

[BigBlockTrucks]

My 65 has disc on the front and functions quite well using the original single pot master without power assist.

[swptln]

My 65 has disc on the front and functions quite well using the original single pot master without power assist.

How can you be running a single master with disc's? Single masters have a residual check valve, you must be chewing up front brake pads like crazy....

[BigBlockTrucks]

My 65 has disc on the front and functions quite well using the original single pot master without the power assist.
[/quo

How can you be running a single master with disc's? Single masters have a residual check valve, you must be chewing up front brake pads like crazy....

The truck still hasn’t left the property yet. So technically I guess I’m not running it yet. The plan is to convert to dual master with vacuum assist. I didn’t know about the residual check valve. Does it essentially bleed off the pressure in the lines so the calipers release?

[PwrWgnDrvr]

Dual masters have the RPV also. Clutch masters don't. Google "residual pressure valve". The purpose is to let the pressure release slowly for smooth braking. Unlike a clutch where u need instantaneous pressure drop. The rpv is found under the brass seat in the outlet port. Also see the FSM for service procedures.

[BigBlockTrucks]

Dual masters have the RPV also. Clutch masters don't. Google "residual pressure valve". The purpose is to let the pressure release slowly for smooth braking. Unlike a clutch where u need instantaneous pressure drop. The rpv is found under the brass seat in the outlet port. Also see the FSM for service procedures.

Can the RPV that is under the brass seat be removed without ruining the master?

[PwrWgnDrvr]

Yes, procedure in the FSM.

[swptln]

Dual masters have the RPV also. Clutch masters don't. Google "residual pressure valve". The purpose is to let the pressure release slowly for smooth braking. Unlike a clutch where u need instantaneous pressure drop. The rpv is found under the brass seat in the outlet port. Also see the FSM for service procedures.

Can the RPV that is under the brass seat be removed without ruining the master?

No, the single pot master has the check valve inside the main bore. Unlike the dual master, where there are two separate valves for each outlet as mentioned by Terry. The residual check valve is a check valve and is designed to keep residual pressure on all your wheel cylinders, it releases the high pressure and then closes. Otherwise you would have excessive travel on your brake pedal every time you went to apply the brakes, Brake shoes are designed to have a little drag when the brakes are released unlike disc's that need to release the pressure completely. Two completely different designs.
You also need a proportioning valve when you are running front disc's and rear drums. Proportioning valve is designed to work with a dual master cylinder only. There is a special valving setup in a proportioning valve that is designed to apply the rear brakes ahead of the front's based on the amount of pressure applied, to help in settling the rear suspension of a vehicle, due to the fact that the front discs will have more braking power than the rears. Otherwise you would lose traction or the possibility of actually having your rear tires leave the road. Severe nose diving of the vehicle.