Thread: 34 going up on jack stands for a while

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. . . but it wasn't, and probably never will be. I was not happy with the braking, so I'm upgrading.

I had GM metric brakes on the front and Ford Explorer brakes on the rear. The front seemed to hold fine, but the rears never worked well.

Brakes2.jpg


Brakes.jpg

I haven't been able to drive it much because my wife had a health problem and had to spend 6 weeks in a skilled nursing facility. I was back and forth to see her there, and for the last 6 weeks, she's been having physical therapy at home.

So, If I can't drive it, I might as well work on it.

what size and type master cylinder do you have ?
Do you have drums on back?

Let me know how you make out with the "parking brake". I've got the same setup and don't think much of it!

See below: Never had drum brakes on the back. Master cylinder is mounted high, and I have a proportioning valve in the rear brake line.

Ultra Light Weight GM Universal / Corvette Style Aluminum Chrome
1 1/8 inch Bore; 9/16" & 1/2" Ports on left Side; disc/disc
Master Cylinder has a piston adapter that will allow for power or manual applications.

For DISC/DISC Applications

MBM part number MC2912ACH

Rears never worked well? but you had a proportuning valve in line to rears to reduce the pressure???? don't make sense???In your picture on the table you got drum backing plate/shoes, discs with internal drum parking brake , Wildwood and oem type calipers------


did you have explorer drums or discs?? never mind I see you said you never had drums on rear---------


Disc brakes take more line pressure and are rarely decent feel with manual master cylinders and I also think that 1 1/8 inch bore would be pretty hard to push without a good size booster. Have you ever put gauges in to read pressures??

Proportioning valves limit pressure, not volume. If your rear calipers are of different volume than the front the backs or fronts may never work even with a proportioning valve, even with a disc/disc master cylinder. I got a hard lesson from Wilwood tech guy on this, running wilwoods on the front and was planning on running GM's on the back, they reassured me its being done but the GM's are never going to collapse due to more volume than the wilwoods, even though I had an adjustable proportioning valve, he told me it won't limit volume. Hit a rod run its being done all over but at least the fronts tend to be the smaller volume and these guys are doing their braking with them (thankfullly) Call master power brakes ask them the scenario see what they come up with. Also thats a great looking hotrod you have! Best of Luck Matthyj

Originally Posted by jerry clayton

Rears never worked well? but you had a proportuning valve in line to rears to reduce the pressure???? don't make sense???In your picture on the table you got drum backing plate/shoes, discs with internal drum parking brake , Wildwood and oem type calipers------

Disc brakes take more line pressure and are rarely decent feel with manual master cylinders and I also think that 1 1/8 inch bore would be pretty hard to push without a good size booster. Have you ever put gauges in to read pressures??

Jerry,

I put in the proportioning valve to tune the brakes front to rear. However, I've always had to have it wide open. No, I don't have a pressure tap. If this setup doesn't work, I'll do some more measuring.

By the way, I had this same master cylinder with manual disc/disc brakes on my full-fendered steel A-Bone with a big block chevy, and it stopped on a dime.

there is no zero on a proportuning valve-they are at about 20% (IIRC) starting range. Do you use one of those combo thingies near the master and propor in the line to the rear?
and whats your pedal leverage ratio?


I'll be down by Springfield , Virden, Girard, Carlinville and over to Manchester in a few weeks-any thing you'd like a snap shot of? Old school, bar, gas station, street address?

I have an Allstar 48025 proportioning valve in the brake line to the rear, and no combo valve at the master cylinder. The Allstar info sheet says adjustment goes from full pressure to 57% of inlet pressure.

Having logged 1200 miles on my Wilwood brakes, I find that I'm still a little disappointed in the braking force, even with a smaller 1" bore master cylinder and a dual 7" diaphragm vacuum booster. I would not use a 1-1/8" master, unless your brake pedal has a large leverage ratio. I'd like to find a 7/8" master or maybe try an 8" dual diaphragm booster, but it will hang down another 1/2" and may touch the floor of the car. The brake pedal leverage ratio is also relevant. Mine is about 4/1.

I have a classic tube brand proportioning valve for the rear brakes, but like you, have mine wide open and the front tires are still the first to lock up.

The drum type parking brakes will not work well at all with a Lokar emergency brake handle. I spent big bucks and put an e-stopp electric operator on mine. It will pull 600lbs on the cable.

E-Stopp Brake

Jack are you still having problems with your brakes??????

Replaced the master cylinder with a Wilwood high volume master cylinder - 7/8" bore. Replaced the Ford Explorer-type brakes on the rear with Wilwood 4-piston calipers & rotors. Increased my brake pedal ratio from 6.25:1 to 7:1. It's all good now.

Sounds much better--------sometime s questionable brakes makes a sucking sensation in the seat cushion

I'm probably going to the Scottville Il Labor Day pick nic with family members--cutting thru the area down by Virden, Girard, Aubrun---any photos you d like ????? Some day want to see Stan Lominlino

No thanks, Jerry. I still have a bunch of family, friends and schoolmates in the Virden and Auburn areas. They keep me pretty much up to date on changes and happenings. But thanks for the offer.

Originally Posted by 34_40

Let me know how you make out with the "parking brake". I've got the same setup and don't think much of it!

With the big rear tires (lots of leverage) and the marginal pull of the Lokar E-handle, they're not what I would call anything better than OK. They would never be an E-brake; however, they will hold the car OK on a hill. They don't hold too well if I have to run the engine up in gear to set the timing, but they will hold. I don't much care how effective they are, as they got me through inspection, and I never have to have it inspected again.