I just thought I would share an update with PDQ, MarkM and others that have helped me with my Cheap Big Brakes. Spring is coming early this year so I should be able to road test in the next few days.

I went with 13 inch rotors on the front (95 vette) with a single piston truck caliper.

http://memimage.cardomain.net/member_images/6/web/2310000-2310999/2310023_4_full.jpg

http://memimage.cardomain.net/member_images/6/web/2310000-2310999/2310023_3_full.jpg


The rears are 12 rotors from the same vette with a single piston caliper from an 89 camaro. I went this route since finding donor stuff in junkyards is impossible in this area and because I bought one of the calipers (new) off ebay for 10 bucks. I think they are small enough that my balance should be reasonable. We'll see! They have built in e-brake (I made the arms). The only down side is that the bleeder is pointing down, so I had to unbolt them and tirn them over to bleed the brakes. No biggie...

http://memimage.cardomain.net/member_images/6/web/2310000-2310999/2310023_5_full.jpg

http://memimage.cardomain.net/member_images/6/web/2310000-2310999/2310023_6_full.jpg



Thanks again to PDQ for sending me the templates and everyone else for my questions. Let me know if anyone has any questions and I will do my best. If interested, I will let you all know if this things actually stops in a few days!

Robb

robbm,
That looks pretty sweet! Couple-a-questions, if the bleeders were on the bottom could you have swapped sides with the calipers? Right side on the left and left on the right to put the bleeder up top? Are you using two right side calipers? Or possibley mounted the brackets/calipers towards the front? I just upgraded to 4 wheel power discs but in the future I might go pro-tour with a hotchkis setup and the big brakes and cross drilled rotors.

I was thinking the same thing, swapping the calipers side for side should place the bleeders up.

What master cylinder...?

I'm glad I could help out here...

Your's are prettier than mine b/c I didn't paint anything except the brackets are black

pdq67

If he swapped calipers side for side, the hose connection would be opposite. However, this could be a good thing as it would fill the cylinder/caliper up from the bottom.

If he rotated the bracket 180*, then the shock would be in the way of the caliper, either side.

Well, what I found was this... the rear calipers are the 'non performance' 4wdb option on an 89 Camaro. There is only 1 part number for both sides. Not having actually seen them on an 89 Camaro, I would say that they are staggered exactly opposite what's needed on a 68. As someone stated, to orient them the same as they were intended they would interfere with the shocks.

I don't think this is going to be a big issue. To bleed the brakes I removed the calipers and hung them from the bumpstop above the axle. Got a block of wood that just fit into the caliper and let them squeeze that!

The master is from a 72 vette. My car has the short push rod but luckily when we swapped all of my stock disc brake stuff on to my fathers 68, he had the long push rod so we just swapped. Also running an adjustable prob valve right under the dist block (which came from dads 4 wheel drum car)

They're now saying rain on the weekend after an amazing week of sunny days so I'm not sure if I'll get to road test soon or not.... I'll let everyone know if it works.

Thanks
Robb

robbm,

Have you got the "pdqCBB" sorted out?

And if so, how do they work?

pdq67

Well it's been a little aggravating for the last few weeks for a variety of reasons. Initially as I had mentioned here in another post, I had a lot of trouble getting a good pedal. It wasn’t really noticeable until the car was running and assisted. I bled, re-bled, cried, swore, and bled some more…. with little improvement. I finally removed the MC and started to bench bleed again but got no bubbles. Then on a hunch, I put a pry bar between the vice jaws and the MC to cause the front to be tipped down a few degrees. Got lots o bubbles this time. Back in the car, it fixed the spongy feeling but the pedal is still a little low (but acceptable). I had my local speed shop guy drive it last week and he feels that the pedal height/feel is what should be expected from a 70s vette master. He thought the car stopped better that any other muscle car he’d been in!

The front brakes flat stop! It’s only been the rears that I’ve been working on. The 88 Camaro calipers with built in e-brake seem very difficult to get adjusted. It seems that I always have one side or the other that is not applying the e-brake fully. I think this could be related to the pedal height problem, still playing with it. At this point, I have the prop valve dialed all the way in to max the rear brakes, but I cannot lock up the rears. I may remove the adjustable prop valve to see if it’s still cutting the pressure some.

All in all, I think it is going to work out just fine! I may look at using a wildwood mechanical spot caliper as an e-brake and run a metric front caliper on the rear for my pdqCBB4WDB V2.0.:) The biggest problem hindering my testing is a new carb that has been a dog’s breakfast so far. It was supposed to go back to the speed shop today but it’s been raining all week. I will let you know in another week or two how things are progressing.

I'll post some pics soon of the e-brake setup, etc...

Thanks
Robb

I'm attempting to use a 1.25" piston Van M/C for volume!

I will know onna these days if it works out and if it doesn't, I will try smaller ones until I find the biggest smaller pistoned M/C that works!

pdq67

Rob,
Those rear calipers are a big PITA IMO/E!

One thing you could try is the front caliper off a mid 80's camaro or similair as I believe those would be the same caliper, only without the ebrake part. They are much cheaper and easier to use. That's probably the route I'm going to use.

What did you use for brackets for fronts and rears? I'm just finishing up a prototype bracket for my version of the PDQ CBB version 1x! I'm going to be using a 12" rotor, the drum hub and single piston suburban calipers. I plan to keep mine manual brakes... sounds like you went power assist? I'm not doing the rear swap until I get a new rearend to replace the peg-leg 8.2".

So far my costs have been $70 for both front 12" rotors (Powerslot rotors even!), about $50 for both front calipers loaded, and about $20 for the piece of steel to make the brackets. Thanks again to pdq for the templates....

Anyway, I'm real interested in your trials... maybe it will make mine easier!

It will still be a while tho till I can really test it as the car's front end is still out and no motor or tranny yet! (Actually just picked up a 700r4 cheap today!)

Good luck,
Bill C.

Edit: PS. I also wanted to know what application the front caliper is from... you said single piston truck, but it doesn't really look like one! Do you know the diameter of the piston?

Thanks.

My front calipers are 2-15/16" big single piston like the '69 and newer cars, but they are a 1/4" wider at the pads for use on the Vans due to their 1.25" thick rotors.

Not the great big jobbers, they are HUGE calipers!! Off the bigger trucks!

pdq67

PS., fwiw, stock rotors are like 1.00" thick;

'88, 'Vette, 13" fronts are 1.10" thick; and

the Van's and some h-d 'Vette and the old JL-8s are 1.25" thick IF I have the JL-8's right?

I have to concur to David Pozzi here..

I'm attempting to use a 1.25" piston Van M/C for volume!

I will know onna these days if it works out and if it doesn't, I will try smaller ones until I find the biggest smaller pistoned M/C that works!

pdq67

What year/model van is it from? Do you have a part number? I've been wondering if I have a volumne issue. The rear caliper piston is about 1.75", so I though that I would be OK with the vette MC. It's an 1 1/8 bore master (I believe).

I had the car out again on Sunday. Pulled back in the shop and smelled that hot brake smell!! I seem to still be fighting with the rear caliper sticking!!! I gonna burn this F*&%#N car :(

Robb

Rob,
Those rear calipers are a big PITA IMO/E!


So I'm learning :(


One thing you could try is the front caliper off a mid 80's camaro or similair as I believe those would be the same caliper, only without the ebrake part.

I had planned to go that route, but an e-brake in required by law here. They've (police) even started to check for them in working condition at road stops! I have since found a solely mechanical caliper from Wilwood that works as an e-brake. This would allow me to run a front caliper in the rear. I may have a pair of these spot calipers ordered before the end of the week!

http://www.jegs.com/images/photos/950202280.jpg


What did you use for brackets for fronts and rears?


I cut the front brackets from 3/8 plate steel using templates provided by PDQ. The rears are cut from 1/4 plate with spacers welded where the calipers bolt on.


Edit: PS. I also wanted to know what application the front caliper is from... you said single piston truck, but it doesn't really look like one! Do you know the diameter of the piston?


The calipers are from a 72 half-ton. They look different because I ground some of the bumps, etc from the front side of the caliper and made a sheet metal face plate to weld on. I did this on the rears as well.

If there are any questions, let me know... at this point I'm considering redoing the rear brakes using front metric calipers and spot calipers as an e-brake. We'll see.....

Robb

pdq67,
The van calipers are the same as the ones used on trucks with the JB5 & JB7 brake option. I believe up to 80 all 1/2T Chevy trucks had the 1.25 rotors, and after 80 they had the JB3 (1.00 rotor) and JB5 & 7.(1.25 rotor)
You may already know this, but just putting it out for people when they are trying to source parts.

Virgil

Thanks, b/c I didn't!

I just asked my friendly Parts Person to bring several boxes out and I looked them over and measured until I found it!

I do have mine written down SOMEWHERE, but where?????????

pdq67

Well, this has been the longest ‘long weekend’ that I’ve ever put in! I started the weekend with 2 68 Camaros in my shop and no brakes between them!

Problem 1 – Dad’s car. All of the stock front disc parts from my car were swapped to dads car over the winter. He had an incredibly high and rock hard pedal, but little to no brakes. Bleeding the lines showed almost no fluid at the rear. After hours of bleeding, checking rod lengths, changing the prop valve, etc… we started to blow air through the lines with an air hose. We found a solid blockage in the rear flex line. I’ll pick one up to day and hopefully we can get his car back together tonight.

Problem 2 – CBB. Well I ditched the previous rear calipers. I picked up 2 right hand front calipers (metric) from an 80s Mailbu. They were the same overall dimensions as the previous ones so they simply bolted up to my brackets. I also added a Wilwood 2 lb residual valve to the rear line. I finally got on the road last night. This thing FLAT STOPS! How many black marks would you like sir? 2 or 4….. I’m still going to fine tune the bias, but with my prop valve approximately in the middle of its adjustment the rear brakes do not seem to be locking up. What’s a good way to be sure I’ve got this right? I’m thinking I should do some hard stops on a wet road to make sure the rears don’t lock up then either…. Any other suggestions?

I’ve ordered the Wilwood mechanical calipers today from Jegs for my e-brake. I should have them by the weekend. I will then modify or build new rear brackets to hold both calipers.

The last ‘issue’ that I working on is a possible residual pressure problem. Past testing has indicated that even the front calipers were overly tight (rears were being cooked by the e-brake). I was concerned that there was a residual pressure valve somewhere in the system. As part of the changes this weekend, I removed the distribution block that I was using from a 4 wheel drum car because a friend felt that there were residual valves in the block. I didn’t really agree (I believe they are in the MC) but I removed it anyway. I now tee to the front lines and go straight from the MC to the rear. I’m not sure if there’s still a problem. The rears seem fine, but the front might be a little tight. I measured the rod length/hole depth and they seem exactly the same. I’m worried that there is no slack here. I will space the MC with a washer on each stud tonight to see if that changes things. I’m thinking I might need to grind a 1/16 of an inch off the rod.

More results to come in the next few days.

Robb

Hey is this the Pozzi CBB set up?

No, it's like my "pdqCBB" set-up!

Great going!!

Like I've said, the sucker WILL stop or I will install a boat anchor!!

pdq67

Robb,
I'd still like to see pics of your caliper brackets to compare to mine. Mine are still in progress, so any help there is always a good thing!

Also, I'm real curious on the ebrake set up you come up with, please keep us posted!

Thanks,
Bill C.

pdq67,
The van calipers are the same as the ones used on trucks with the JB5 & JB7 brake option. I believe up to 80 all 1/2T Chevy trucks had the 1.25 rotors, and after 80 they had the JB3 (1.00 rotor) and JB5 & 7.(1.25 rotor)
You may already know this, but just putting it out for people when they are trying to source parts.

Virgil

Yes, any GM half-ton pickup or big car would have the 1 1/4" rotor.

The GM "Metric" front calipers have a bore around 2 3/4", they are larger than needed for rear brakes. You can cut the pressure down via a proportioning valve, but remember the larger bore uses up volume and that results in a lower pedal height.

US Brake and some other circle track vendors sell a GM copy caliper in cast iron that has a 2.5" bore.
David

What David just said is why I have to try the 1.25" dia. piston power M/C before I switch anything to see if it works right! (In non-power!!)...

I have an old mag. article that say's that it worked fine for applications using the calipers that my "pdqCBB" system uses.

pdq67

pdq67 sorry I didnt read enough to give you credit lol.

Arent the 95 13" rotors 1.1" thick? How thick is the mounting face?

The 95 rotors are 1.1 inches thick.

PDQ - what is that 1.25" MC from? Any idea would help. I would possibly consider trying it out. I have decent pedal height/travel, but the extra volume may make it better! I guessing it may require a little extra pedal effort (I'm running power) but that shouldn't be an issue. Gimme a clue... :)

Thanks
Robb

It's a standard 1.25" piston power M/C off a van!

I found it by again, asking my friendly parts person to haul out several M/C boxes as I hand MEASURED their pistons!!

I had to make a little p/r holder out of a 1.5" copper waterline sweat-on cap by cutting it so that it fit just over the rubber boot groove. I hand cut it so that it was like a 1/2" tall??

I then drilled the hole for the p/r and then peined it on the M/C using a center punch "indenting" it into the groove.

The HARD part was that it took me like 5 to 6 try's to set my p/r length so that I HAVE about .060" p/r to piston clearance!!

It was a REAL drag setting my adjustable p/r and then mounting the M/C, checking it with my head under the dash and my as-- up in the air, doing it again AND again UNTIL I got it right!! Flashlight and all!!

pdq67

PS., I made my p/r using a Grade-8 bolt I threaded longer cut to fit and "bull-nosed" is all....

here's a bore area chart:
http://www.outlawdiscbrakes.com/faq.html