[HWYSTR455]

Those speedmaster kits are 'universal', can see the multiple bolt patterns on the brackets in the pic, but sure you saw that after posting.

Was also pointing out that the calipers offered by Speedmaster are new, not rebuilds, and are probably in the same price range as rebuilds.

Oddly, I've never had a problem with Pirate Jacks, but maybe things have changed.

If the issue is with the front brake lines not getting any movement/flow, not sure you need to bail on the rear ones, if they work. Just need to figure out the fronts.

Shouldn't be too hard, it's something with the master. If they bench bled it, then it flowed on the bench, so I still would have to think it's something with the booster/master relationship. Maybe the pedal, but kinda doubt that.

If you bail, then it's a total loss of funds, but your call obviously.


.

[NeighborsComplaint]

Originally Posted by Scarebird

Not true - we designed a different type of setup using a formed center and later a drum-in-hat setup.

OK. almost all the "cheap" systems use the Eldorado rear calipers. Pirate Jack's kit is the same as Inline Tube's which is the same as yada yada. All include brand new calipers. See any similarity?

Summit


Right Stuff


Leed


Speedway (incl splash shields)


Inline Tube


Pirate Jack's
(complete front & rear only)

[Scarebird]

We had the better mousetrap but not 1/1000th of their marketing might.

[Schurkey]

Originally Posted by NeighborsComplaint

OK. almost all the "cheap" systems use the Eldorado rear calipers. Pirate Jack's kit is the same as Inline Tube's which is the same as yada yada. All include brand new calipers. See any similarity?

Every one is flat-bracket garbage where the caliper mounting pins have to accept caliper thrust--which the pins were never intended to do.

"Engineered" by a doofus who might as well have been in high-school; didn't pay attention to how the OEMs dealt with caliper thrust. "Winged-it" and it "fits" and "works" at least for awhile.

[Scarebird]

As stated previously, our stuff has been using a formed center the same thickness as the OEM drum backing plate, see below. This also allows a far stronger part and flexibility in assembly offset.

Shcurkey - your statement concerning using the pins as load bearing is foolish - a simple look at the pix NC put up show the brackets indeed grab the body of the caliper as ours did with our first item 20 years ago.

[Schurkey]

The OEM systems take the caliper thrust "even" with the rotor, between the pads. The caliper thrust is centered, so there's no twisting force on the caliper, the pins, the rubber O-rings the pins ride on, or the pads. This is visible on the parts associated with the front disc system in the Pirate Jack photo. The caliper mounting bracket isn't "flat", it's got formed "fingers" that accept caliper thrust (forward and backward) in the middle of the caliper.

Flat-bracket junk takes the caliper thrust on the inboard part of the caliper, even farther inboard than the inside pad--way offset from the "centered" arrangement the OEMs insisted on. The thrust is therefore offset, leading to twisting and thrust stress on the mounting system that the caliper, pins, and pads weren't intended to take.



The enormously better way to do this is to use the sort of caliper and mount where the pads sit in an iron holder mounted firmly to the backing-plate or strut or whatever; while the caliper has no thrust at all--it merely clamps the pads. All the thrust is taken by that iron holder, designed from the beginning to deal with pad thrust.

Or

Don't use a "flat" bracket to hold the older-style caliper. Add the sort of "fingers" that will take the caliper thrust between the pads exactly like the OEM intended and designed-for, instead of thrust offset to the inside .

[hgerhardt]

Originally Posted by NeighborsComplaint

..........are the factory brackets held by bolts requiring a second set of hands under the dash or are they pressed/welded studs?

If it's a 64-72 A-body or 67-69 F-body, the studs are welded to the pedal support and protrude through the firewall forwards into the "hot" side. So you do not have to hold anything. Just unbolt the nuts from the engine side.

This is unlike what 70-81 F-bodies or 73-77 A-bodies or 77-96 B-bodies use, which is studs welded to the booster with nuts on the cold side of the firewall.

[Scarebird]

Originally Posted by Schurkey

The enormously better way to do this is to use the sort of caliper and mount where the pads sit in an iron holder mounted firmly to the backing-plate or strut or whatever; while the caliper has no thrust at all--it merely clamps the pads. All the thrust is taken by that iron holder, designed from the beginning to deal with pad thrust.

Or

Don't use a "flat" bracket to hold the older-style caliper. Add the sort of "fingers" that will take the caliper thrust between the pads exactly like the OEM intended and designed-for, instead of thrust offset to the inside .

No.

When the caliper clamps down on the rotor it automatically stops the the rotor from twisting, even if not locked up - the extra fingers are superfluous. They do however stop the caliper from being mounted crooked. and the weird pad wear/binding that results. But if you note the aftermarket brackets with "fingers" as you put it usually have a 0.050" or greater gap, negating any advantage.

In short, they work adequate to the task
GM's second generation of caliper is far superior.

I would be more concerned with the bolts and shims.

[Schurkey]

Originally Posted by Scarebird

No.

When the caliper clamps down on the rotor it automatically stops the the rotor from twisting, even if not locked up - the extra fingers are superfluous.

I don't care about the rotor twisting. I care about the offset mounting leading to a caliper-twisting force.

Apparently, GM also cared about this since their mounting system with centered-thrust doesn't lead to a caliper-twisting force.

Originally Posted by Scarebird

the aftermarket brackets with "fingers" as you put it usually have a 0.050" or greater gap, negating any advantage.

I've never measured the gap between the OEM caliper mount thrust surface, and the caliper. Ideally, it wouldn't be too large; the thrust would still be centered (advantage) but the total movement of the caliper could stress the pins 'n' O-rings.

Originally Posted by Scarebird

GM's second generation of caliper is far superior.

Is that "second generation" the style where the pads are captured in a bracket separate from the caliper? If so, I agree. I have that style on my '92 and '93 Luminas; and on an '03 Trailblazer.

The calipers and pad-mounting brackets may/may not be suitable for use on an A-body based on piston size, rotor thickness, and the mounting system required, but the concept is wonderful.

[NeighborsComplaint]

Originally Posted by hgerhardt

If it's a 64-72 A-body or 67-69 F-body, the studs are welded to the pedal support and protrude through the firewall forwards into the "hot" side. So you do not have to hold anything. Just unbolt the nuts from the engine side.

This is unlike what 70-81 F-bodies or 73-77 A-bodies or 77-96 B-bodies use, which is studs welded to the booster with nuts on the cold side of the firewall.

Thankyou! I can proceed single-handedly instead of relying on my good-natured, musclebound buddy who doesn't know how to use a wrench. When I pointed out the inclination angle of the master cylinder only lets you half-fill the reservoirs and what a pain it is to install the reduced anglere brackets, he suggested (in al seriousness) he could put a vice grip on the master cylinder mounting studs and bend them down at an angle for me. lol.

Nice guy that'll give you the shirt off his back, I just don't let him near the car with tools.

[Scarebird]

Originally Posted by Schurkey

I don't care about the rotor twisting. I care about the offset mounting leading to a caliper-twisting force.

As stated, it is not an issue. Aftermarket has been building this way for 50+ years.

To correct my statement, clamping on the rotor prevents the caliper from twisting., so your point is really moot.

[NeighborsComplaint]

Well, the comedy of errors is finally over and I have a working 4 wheel disc brake system that stops like a normal car according to the shop. I'll know for sure when I test drive it tomorrow.

As I mentioned, replacing the rear calipers with Eldorado front calipers, the front D52 calipers no longer worked. The shop pulled the master off and bench bled it again and it worked fine. On the car, no fluid flow to the fronts.

I suggested they try the recessed cup master I had bought and the longer 4-15/16" pushrod and damned if it didn't work just fine. They test drove and bled the 4 corners one last time and gave it their blessing.

Somehow, the deeper dual diaphragm booster didn't provide a long enough stroke to provide front braking with the shallow cup master cylinder even though checking said it was on the money with the short 2-5/8" rod. I thought the recessed cup master just used a longer pushrod to compensate for the location of the piston cup but I guess internally, they are different master.

While trying to find a shop to work on it, I stopped at a highly regarded best brake and alignment shop in town who all but slammed the door in my face. I told him I was having problems with the rear brakes on a rear disc conversion and wanted them to see what they could they do to improve the stopping. The shop's owner said "What makes you think I want your problems to become mine?" I responded in kind saying "I'd heard you were a cockey little xxxx, it's reassuring to know they weren't rumors." and left.

All's well that ends well. At this point, I am just happy to have found a mechanic who was capable and willing to take on the project. I haven't gotten the bill yet but honestly, I don't even care about the cost at this point.

[Scarebird]

I am glad that worked out for you.

[NeighborsComplaint]

Thanks! Drove it today and it feels and stops like a modern car. Nice pedal height, good modulation and nice firm feel plus that satisfying little "bump" when the car stops that tells you the brakes actually grab. What an oddysey this 4 wheel disc conversion turned into. $660 labor plus calipers, pads, a couple different master cylinders and a new proportioning valve for good measure and worth every penny to get it sorted out.

[NeighborsComplaint]

Originally Posted by Scarebird

The fronts may not fit; too big (2-1/8" vs. 2-1/2").

Do you have an extra caliper lever laying about?

I've got both R&L caliper levers. PM your mailing address and PayPalo me the shipping later.