vaccum brakes/best set up

[Louie L.]

Is there a better vaccum set up for our cars. Im looking for a decent pedal feel and stopping. Is there something better as far as running a different master cylinder, like from a B body ?

Also what effect does master cylinder size( like bore size) have on breaking?

Currently the PM stops the car very well at the track, I do have Aerospace rear disks, stock fonts,deleted factory prop valve, adjustable wilwood prop valve. But the pedal feels like crap and wont hold the car with the line lock to do a burnout. So im going back to vaccum.

 

[John Larkin]

Maybe you want to talk to Odell. He runs a manual m/c from a truck. Since you have a track-only car, might be the simplest solution. Kendall is using a plastic Mopar one, manual as well. I checked out the B-body m/c and after alot of research, it was determined that the braking power of the vacuum G-body m/c was superior. This was due to the larger bore of the B-body requiring even more pressure to do the same job as the G-body. Sounded like a load of crap at first but the argument was fairly convincing. I have no problem holding the line lock with my vac setup.

I am interested in hearing more about your Wilwood prop valve conversion. Did that help your pedal dramatically? Maybe it's a contributing factor to the line lock.

You may find that adjusting the e-brake properly (there's a procedure in the service manual) might help with pedal feel though it doesn't affect the front calipers.

 

[Louie L.]

John ,
Thanks for the info. I should have mentioned that my system has performed flawlesly untill just recently. I have always had good results with a powermaster and thought that my set up was the cats meow. I have actually fixed a couple of them and got em to work great.The prop valve swap was one of the best things ive ever done to my car. I was able to hold about15 psi with the stock rear drums with out trying hard at all . The brake feel was nice.

But lately after the car sat for a while the pedal feels like crap and the brakes just dont work right. So Im finally all done with the power master.

I would love to go manual but it not allowed in TSM And i cannot adjust the e brake cause i donto have one any longer with the Aerospace rear discs.

Thanks for the help.

 

[John Larkin]

Well, if your a junkyard diver, the only advice I can offer is try to find a good booster. Some leak. A clue is the condition of the boot on the rod; if it's shot, chances are the bladder is too. The first one I pulled ended up being junk. The 2nd one was from an '85 Regal. When I pulled the check valve out, there was still vacuum in the booster! I knew then that I had found a good one. A new m/c is $29 or so. J/yard should be less than $20 - 30 for the whole deal.

If mine don't hold boost after my adjustment, I'll probably go with the Wilwood prop valve as you have. You don't worry about the adjuster knob moving? Is yours under the car? You don't drive on the street at all do you?

 

[lazaris]

Louie,

I would look into this system.
http://www.hydroboost.com/products/index.html

 

[Red Regal T]

I was curious about the BBody master cylinder. I read about the larger cylinder taking more pressure. I thought larger pistons make more compression. I have vacuum brakes. I had the stock G-body master cylinder. The car stopped fine. I changed over to the B body master cylinder. On the first drive my brakes felt better. That's the only time you can compare the feel. I continue to use the B-body MC. Now I'm not saying this will be the case all the time. I really don't know. I think there is a lot of factors in making your brakes better. I have an 87 NA regal and the brakes seem better than on my T. I have a GN that I changed over to vacuum and it seems to stop better than my T. Same kinds of cars.....same systems......but they all feel a little different. Makes sense.

 

[Scott Atk]

Anyone have any additional info on the Mopar MC? I know its popular with racers. Can it be utilized with a vacuum booster? Or is it strictly manual?
Thanks !