Tell me what is wrong with my set up.

[LowBuckX]

The rear Cadillac Seville swap are also 2.406 just with an e brake? Why does that work but not mine? Also the WS6 calipers are the same

[andrewb70]

The rear Cadillac Seville swap are also 2.406 just with an e brake? Why does that work but not mine? Also the WS6 calipers are the same

Good questions. I am not sure that I can give you an answer from my living room. One theory is that those cars used a bigger bore MC. As far as the balance issue, many things such as front rear weight distribution, suspension geometry, springs, shocks, etc...will all play a part in how balanced the systen will be.

What year Seville and WS6?

Andrew

[sinned]

1 1/4" master and an adjustable rear balance valve (also known as an adjustable proportioning valve). Andrew is correct about the size of those calipers, they are fairly big. I’ll bet both the Seville and WS6 run at least 1 1/8" bores which is why they work.

Yes, a pressure bleeder will work much better than a Mity-vac.

[LowBuckX]

85 caddy Seville Master acording to www.napaautoparts.com The !985 Cadillac Seville Master is a 1 inch bore.... But the pic looks to be of a QTU type master. http://www.napaautoparts.com/masterp...linder+-+Remfd

[andrewb70]

85 caddy Seville Master acording to www.napaautoparts.com The !985 Cadillac Seville Master is a 1 inch bore.... But the pic looks to be of a QTU type master. http://www.napaautoparts.com/masterp...linder+-+Remfd

I found the 85 Seville MC listed on the RockAuto website. The AC Delco PN is 18M186. The discription reads: 25.4 and 36.0mm cylinder bore. That means it is a quicktake up style MC that is similar to the one I am using on my GTO. I bet anything that the 36mm bore port is for the rear and the 25.4mm port is for the front. Makes perfect sense given the large piston area of the rear calipers. On my GTO I have the rear port plumbed to the front since my 6 piston calipers need more volume.

Andrew

[LowBuckX]

Now all I need to do is find a way to see how the factory has the 85 seville routed. This guy has an 86 Camaro Master running his swap that is the same as mine. I see he has the front portion of the Master running to the rear.
He claimes he has a firm high pedal like Im looking for.
You can see his Adjustable prop valve plumbed to the front section of the master.
He has the snout of his master turned down to 1.48 to fit in his booster.

Is it possible to cut down the push rod on the booster seeing I have the deep style and the QTU takes a shallow style?

But the Camaro Master according to Rock auto is 24MM and 31.75mm so the seville may be a better choice

[andrewb70]

Now all I need to do is find a way to see how the factory has the 85 seville routed. This guy has an 86 Camaro Master running his swap that is the same as mine. I see he has the front portion of the Master running to the rear.
He claimes he has a firm high pedal like Im looking for.
You can see his Adjustable prop valve plumbed to the front section of the master.
He has the snout of his master turned down to 1.48 to fit in his booster.

Is it possible to cut down the push rod on the booster seeing I have the deep style and the QTU takes a shallow style?

But the Camaro Master according to Rock auto is 24MM and 31.75mm so the seville may be a better choice

At this point I think you will just have to experiment. I think getting a larger bore MC is definitely going to help. The guy with the 86 Camaro MC no doubt has a very nice firm pedal considering he plumbed the 31.75mm (1.25") piston to the front brakes. The question is how effective are his rear brakes with the 24mm MC bore being plumbed to them. His rear brakes may not be doing much of anything. With the large bore port plumbed to the front he is getting the illusion of great brakes. Firm pedal, fast responce, etc....Just thinking out loud..

Andrew

[David Pozzi]

Get a stock 1 1/8" cast iron master cyl for your car, that is what it should have used originally. Your front calipers need the 1 1/8" bore MC.

Your rear calipers may work OK with this combo. some of the Ford rear calipers are over 3" bore and those really cause a low pedal. Avoid the Quick Take Up MC if you can, it's hard to find a good one that works well and they are a pain to bleed.

[LowBuckX]

Should I just get a 1 1/8 Disc disc master Ala 68 vette with power brakes. Still fairly inexspensive.
I am PMing you David on an Idea Ive come up with.

[LowBuckX]

Well I have been given some missinformation. The seville rears even though they share the same mounting and basic shape of the fronts Only have a 2.121 piston. But the 79 pontiac TA rear caliper has a 2.49 piston.

[EastCoast]

I'm just in the process of finishing this same basic setup. Single piston caliper on the front with 13 inch rotors. Single piston 'metric' calipers on the rear from an 81 Malibu with a 12 inch rotor. I'm using an 1 1/8 MC from a 72 vette with a 2lb residual valve in the rear line and an adjustable prop valve. Still fine tuning, but it seems to working out.

There's some details of my trials & tribulations over here....

http://www.camaros.net/forums/showthread.php?t=77947

Hope it helps

Robb

[andrewb70]

Well I have been given some missinformation. The seville rears even though they share the same mounting and basic shape of the fronts Only have a 2.121 piston. But the 79 pontiac TA rear caliper has a 2.49 piston.

Misinformation? On the Internet? How is this possible?


2.121" is still pretty big, but definitely better than 2.49". Try the 1 1/8" MC and I think you will be good to go.

Andrew

[BRIAN]

Why don't you start from the basics before you go swapping out parts. Residual valve on the rear correct? Have you tried full out and full in?

Actually I would first take a vacum reading at the booster to verify correct vacum to operate booster. Than I would take off the front and rear lines and plug the master cylinder to verify it is working properly? You did bench blead the master correct? The rod for the master is on the right hole on the brake pedal? Those rear calipers are notorious for bleeding problems. Invest in a Motive pressure bleeder. Makes easy one man bleeds and is relativly cheap. Try tapping on them it usually frees up some air. The Mityvac is probably your biggest problem but that is another story.

If all from there is ok than start with the swapping of parts. Call Mater Power brakes or look on their web site. They are great source of free info

I am running Metric GM calipers in the front, Seville rear calipers and a 1" master. I have perfect vacum but could only fit a 7" master. With some playing it has firm but great stopping power with simple Hawk pads. The pads were probably the best investment on that system. Not one special part needed.

Good luck.

[LowBuckX]

Hi brian I will aswer your questions in order.

Residual valve on the rear correct?

Not sure 2# for discs where recommended

Have you tried full out and full in?

On the adjustable valve.. if so yes

verify correct vacum to operate booster

Booster is proven to work

You did bench blead the master correct?

yes I did a second time to make sure

Invest in a Motive pressure bleeder.

Built my own out of an ace garden sprayer and odds and ends I had around the shop. Works awsome that is why Im sure I have 0 air in lines.

I got a 1 1/8 disc disc master today. $16 plus $5 core via advance auto.
Will try it in a few minutes..

[LowBuckX]

Ok my pedal is up like I like it but I cant say forsure if it is right yet till I bleed it again

[BonzoHansen]

Built my own out of an ace garden sprayer and odds and ends I had around the shop. Works awesome that is why I’m sure I have 0 air in lines.

Someday, when you have time, you need to show that little contraption!

[LowBuckX]

Well good News I have great pedal now after the 1 1/8 master.
I originally started with a 1 1/8 disc/drum Master and it didnt work thats when I went to the 1" disc disc as recommended by someone who got his to work.
Now Im gonna screw it all up again and do a pdqCBB front set up or some thing close.
BonzoHansen I started a new post with a pic of the so call contraption.

[BRIAN]

The problem with those Vette style masters is there are about 20 different versions out there. Than throw in the offshore stuff marketed as disc or drum and you can see where there can be problems. I went through 3 before I invested in a stainless sleeved deal and has been perfect since. Try some better pads you will be impressed, at least I was. Bought Hawk pads I think at Pep Boys and will never go back to stock.

Glad it worked out for you.