Hey guys, not sure where to post this exactly since it's dealing with my new spacers and also a maintenance/unkown issue.

I drive a 2003 Track Edition Z

I ordered 4 20mm hubcentric spacers with new 60mm studs from Z1 motorsports. Went and had them installed today...looks great (pics to come) but on my way home I noticed 2 things (neither of which were present before the install). Driving down the road, the initial pedal press is a bit mushy...moving about twice as far as it normally did...but if you let off and immediately follow with another press it's nice and firm like normal.

Second thing, there's a pulsing squeak now coming from the brakes. Sounds like a wear indicator, but I have at least 50% on the pads so the indicator isn't even close to touching.

There's no vibration in the steering wheel, and no strange feeling in the pedal besides that initial mushy push.

The surfaces of the hub, rotor, and back surface of the wheel were cleaned with a wire wheel. All studs were fully installed. We also checked the lines for any air bubbles, and the fluid level is just fine.

I spoke with Z1 Motorsports, and they suggested that perhaps the booster valve could be going bad...but how does that explain the sound? It WASN'T there before the install...and the brakes weren't touched besides pulling them off and bungee cording them up out of the way. I'm completely stumped.

Last ditch suggestions were to drive it a couple days and make sure the calipers are seated properly.

Any suggestions?

 

Oh, and on that pulsing squeak...it's only when you're actually applying the brakes. Otherwise all things sound normal

 

No idea what the noise could be, but were the calipers removed at all? If they weren't supported and were allowed to hang from the brake lines, the lines could be damaged. May as well upgrade to stainless lines if you find that the lines are indeed the problem. Agency Power makes a good set.

 

Yes the calipers were removed, but were bungee corded up and never were suspended by the lines. They were my first guess, but doesn't appear to be those...I did plan to do the Z1 Brembo upgrade kit (pads, rotors, ss lines) but didn't want to so soon. I'm really trying to diagnose what's going on right now

This REALLY is getting annoying...I just can't pinpoint or begin to even to guess what's causing this...

 

who did the labor?
and btw, the spacers have zero to do w it.. not sure if you aware of that.. thread title sounded odd.

 

My thoughts exactly...it's the only basis I had to go on considering everything was perfect before the spacers went in...no soft pedal and no squeal. Firestone Complete Autocare center did the labor

 

A couple questions...if it's the brake booster check valve, where's that located? is it on the top coming right off of the booster inside the short hose? or over on the left side of the plenum in the hose running towards the battery?

Another thing that crossed my mind...I DID install the Z1 Plenum spacer yesterday...would that added plenum volume of air somehow affect the vacuum running to the booster? I'm just trying to think of everything possible.

 

Since this started AFTER the install..and it's NOT the spacers..something *happened* when they removed/reinstalled the calipers. Maybe air got in the system somehow. Bleed the brakes.

 

Yeah I'm thinking that's the best plan of action. Hopefully that will cure the soft pedal...but any idea on the squeal? I honestly can come up with what that possibly could be...there's wasn't any debris anywhere, I was all up underneath the undercarriage looking for anything that might be touching, but of course it's only when the brakes are applied...

 

UPDATE

Just bled the brakes...inner bleed first, then outer in a LR, RF, RR, LF pattern per the manual.

I thoroughly inspected the lines as well, no cracks and no evidence of any brake fluid residue. Flushed the whole system with new synthetic DOT 3.

Still have a soft pedal on the first push and a strange sound. I did however check the reliability of that soft pedal push, I still have plenty of bite...from an 80mph stop I can stand on them and really bring it to an abrupt halt.

After lots of reading today on some G forums and other sources, it seems that a lot of guys have "gotten used to" that soft pedal. It doesn't go to the floor so I'm not really suspecting a bad master cylinder considering I only have 53k miles.

Anybody have ANYTHING they could suspect? As of now, I feel better driving it knowing it's safe...just a tad annoying. I believe its possible I might have a very slightly warped rotor that pushes the pads out while not braking, and that extra travel is just the pads getting pushed back to the rotor...however it'd have to be very slight since I don't feel any vibration while braking no matter how fast I'm going.

I've had my eye on Z1's Brembo upgrade kit...rotors, pads, and ss lines...Looks like maybe after Christmas I'll invest in that and see if it cures it. If not then I can at least take away the suspicion that it's rotors, pads, or lines...

Any input is appreciated, guys. Thanks

 

Probably still have air, it is a major PITA to get all the air from the system. Dam near impossible without a pressure bleeder.

 

yeah man I guess that's still a good possibility. I did however decide, after speaking with Z1, to order their brake booster check valve silicone kit to replace the hose off the booster and hose off the manifold.

They did mention the valves tend to start going bad and could in fact cause my issue. Seems to be fairly common. So once those arrive I'll throw them in and give it a test.

If I still have the same issues I'll order their brake upgrade kit and do another system flush to see if I can cure it. Just trying to do the cheap repairs first to narrow out the issue. I'm just not convinced it's a master cylinder issue or a booster issue...and I'm fairly confident in the bleed I just did. Hopefully this thread can be a good reference in the future for others with the same issue.

Again, thanks for your input everyone

 

Another question: Where in the **** do you get a new check valve? Apparently the hoses from Z1 don't include a new check valve, which is what I was suspecting to be bad in the first place.

Everywhere I've looked appears to only have a GM type check valve that is way too big to be installed into the hose. How would you remove the factory one INSIDE the hose and reinstall it into the Z1 hose?

This crap is pissing me off...

 

Well nevermind on the bad check valve. I just went out to check it after seeing as to where specifically it was located. It still seems to be working fine back to my original issues. terrific!

I'm back to assuming there's still probably some air in the lines somewhere