PFC Z-54 front brake system

[VictorH]

I just remeasured everything.
Those thicknesses.for both the stock and PFC include the backing plate.

PFC 28.4 mm with backing plate
Stock 18.45 with backing plate.

I've found that braking performance drops off significantly when you run the pads down to and through the metal.

[dparm]

Originally Posted by VictorH

Measured pad
Endless Track pad
Total thickness .755" - backing plate thickness .223" = .522" Pad thickness

PFC 12 Pad for ZR-54 caliper
Total Thickness 1.128" - backing plate .244" = .884" Pad thickness

LMAO, 1.1 inches?!

[VictorH]

Well, I had hoped to install the brake system today, but didn't go as planned.

Out with the old. Rotor thickness is 29.61 mm (it's reading upside-down).

[VictorH]

Started putting the new system on the driver's side but got stopped.
Caliper bracket mounted and backing plate trimmed to clear the bracket.

[VictorH]

Then when it came to putting the pads on I ran into trouble. I noticed the stainless pads at the top and bottom of the caliper, which I assume are to prevent the brake pad from rattling up or down, on the outboard side were pretty close to the rotor. I measured the distance and it was .015" on the bottom piece but closer to .030 on the inboard side (measured with a feeler gauge). The rotor seemed slightly offset (to the outside)to me or the caliper for some reason was not centered over the rotor. Took the rotor off and made sure there was no junk on the hub and cleaned and scraped around the studs again, but no difference. The caliper brackets are the same and they both measure the same thickness.

When I tried to put the pads on the outboard side they were super tight and you could hardly turn the rotor. I tried to retract the pistons some more, loosed the bleeder on that side but it didn't make any difference. The inboard side was fine, good fit with no issues.

I measured the piston to rotor distance and on the inboard (the good side) got 1.123" but on the outboard side I got 1.092 (with no traction on the piston). You can force the outboard pad in but something's not right so I took it all apart again and will be traveling to work on Monday with the old set up.

Not sure what the deal is. Glad I never took off the brake line or opened the system. Hopefully the passenger side is fine, but I didn't get a chance to try it as I spent the whole afternoon finding and trying to get the driver's side to work, but no luck. I'll call PFC Monday and see what they say.

[ayao]

I don't know this kit well but is there a chance the caliper mounting bracket is flipped or on the wrong side, causing the caliper to not be centered on the rotor? Were you able to maximally retract the outboard pistons?

[VictorH]

Good points but the mounting bolts are recessed in the bracket so no switching inside for out. Part numbers are identical for both and by measurement they seem to be identical.

Tried to retract pistons on the outboard side some more, one was a bit "springy" but wouldn't really stay back. By look and feel they were retracted as much as the inboard side. The only way I could get the pad in was to reach through the backside with the other hand and push the pistons in a mm or so, then I could just force the pad in, but it wasn't right so I just took it all off again.

[SYT_Shadow]

Originally Posted by VictorH

Good points but the mounting bolts are recessed in the bracket so no switching inside for out. Part numbers are identical for both and by measurement they seem to be identical.

Tried to retract pistons on the outboard side some more, one was a bit "springy" but wouldn't really stay back. By look and feel they were retracted as much as the inboard side. The only way I could get the pad in was to reach through the backside with the other hand and push the pistons in a mm or so, then I could just force the pad in, but it wasn't right so I just took it all off again.

It is EXTREMELY tight to put brand new pads into these calipers

PM me if you want a call

[VictorH]

[QUOTE=SYT_Shadow;21671929]It is EXTREMELY tight to put brand new pads into these calipers

Hey Victor,

I think I found the issue! The one installing the pads came up here and mentioned that they were having a bit of difficulty getting the pads loaded in the caliper except it was opposite of the issue you were having (outboard side would go in but the inboard side was a no). What I found is that the anti-knock back springs in the caliper pistons are pushing the pistons lightly outwards. You can push the pistons back in by hand and compress that spring but as soon as you let go the piston pushes outwards again. I would recommend loosening the rotor and getting everything in there (then tightening the rotor back down) and running the car. Once you run around even just a parking lot you should get everything worked out. The rotors do actually have a bit of lateral float in them so that will also work itself out once driven.

Hi Everyone,
spoke with SVT-Shadow yesterday who confirmed what Phil at Bimmerworld sent today. Fit of pads is tight, the rotor is free floating so once everything is installed and you go for a little drive it centers itself and you are good to go.

[SYT_Shadow]

Great! Phil by the way knows his stuff, he's the guy I work with from BW

Let us know once it's nice and installed

[VictorH]

Okay, brief intermission. My car is going for alignment and corner balance next week so I figured it was time to install my rear camber shim kit (it's from Fall Line). I already have their street rear toe arms that I installed a few weeks ago. I'm working this weekend so brakes will go on soon but in a week or two.

[VictorH]

Unfortunately to get the eccentric bolts out you have to remove the muffler if you have a stock muffler or the connecting pipes if you are aftermarket (I am).

[VictorH]

I thought the rear arm would be under a lot of tension from the spring but it's not. You can support the rear arm or you can lift up the rear wheel (with the floor jack) to position the arm so you can insert the replacement bolt (it's still a one person job, but you can't really position the arm with one hand and start the bolt with the other). Shims not in at this point.

[VictorH]

Finishing up. You can see 2 mm offset shim is in. Shims range from zero to 4 mm offset. All bolted back together just need to hook up the connecting pipes. Not a difficult job at all.

[SYT_Shadow]

Victor, what is the purpose of those shims? I can get -2.0 on the stock setup and that's all JRZ and MCS call for in the rear

[VictorH]

Well, it locks things down better than the eccentric. I run -1.5 in the rear, agree that you don't really need more than -.2.0. I don't have a race shop near me so when I take it to the regular tire shop for alignment they never get it right as they tell me the "bolt turns when we tighten it." Which is pretty lame as you just hold the other side with a wrench. It's a bit of a luxury but that way once the camber is set it doesn't change.

[VictorH]

Just got my car back from alignment last night. I'd dropped off at the shop on Tuesday prior to an out of state trip. Front struts upgraded with new bleeder valve and reshimmed and then alignment and corner weights.

Here's what I ended up with:
Camber LF -2.6. RF -2.5
Rear -1.6 both

Weights
985 969
930 914

Left 50.4%
Rear 48.6%
Cross 50.0%

Total with ballast + 3/4 tank fuel - 3799 lbs
Net without ballast - 3639 lbs

[VictorH]

Street pads compared to track pads. Street pads on the left.

[SYT_Shadow]

Have you been able to install the BBK yet?

[VictorH]

Going on this coming weekend. I will document round #2.

[VictorH]

Okay, round 2 of the install. The installation on the driver's side to put the pads in was easier than last time, the passenger side which had never been installed was tighter, just like driver's side on the first install. I guess it loosens up.

[VictorH]

Clearance of 220M wheels is no problem at least 1/2" and my old RAC wheels (sort of like ZCP) fit with same amount of clearance or more.