faulty new rear wheel cylinder? Brake troubleshooting...

[xray]

So I'm still sorting out/troubleshooting the car now that it's back on the road, and I think I'm having some braking issues...

Basically, my car doesn't stop as well as I thought it would. Brakes engage at normal pedal height, but don't seem to want to brake hard and act "grippy." Pedal feel is good, not spongy. Car does not pull to the right or left on braking, and there's no shimmy, shaking or squealing. I just can't lock the brakes, and I think a panic stop for me would certainly involve hitting the object in front of me.:dead:

I may have become used to 21st century braking systems, as my other car (BMW) seems to go 60-0 in 110 ft...The Z maybe 220 ft:eek:

Here's what I've done:

Booster holds good vacuum (18 inches)...all new tubing and check valve (properly oriented). The reaction disk has been properly positioned

BMC new prior to purchase (now three years old)

original brake switch

New pads (carbon metallic from MSA) on known good OEM calipers

All new brake lines

New Brembo rear brake drums and all new hardware

New performance street brake shoes (not track-level performance) http://www.thezstore.com/page/TZS/PROD/PBC03/24-5517

Restored e-brake mechanism (original cable)

BMC bench bled, installed, system properly bled from rear to front.

The ebrake cable is adjusted at the linkage so all slack is removed. Max travel at the ebrake handle is 5-6 clicks, as per FSM. The rear brake shoes were tightened to where the drum won't move, then backed off a couple of clicks on the star wheel.

Problem #1 is as outlined above. Is this just me not used to my car's braking distance and effort? I seem to remember the car braking better before teardown and restore, but that's 3+years ago...Do the carbon-metallic pads/shoes require a warm-up period? I thought since they were "street" pads they would function cold as well as hot.

Problem #2: I still cannot get my ebrake to keep the car from rolling down an incline. It will keep the car still on flat to verrrry slight inclines, but anything worse than that and the car rolls... I noticed today that when adjusting the brake shoes via the starwheel, the ebrake lever on the driver's side wheel cylinder did not have the same ratcheting action as the passenger side. It seemed to bind on the casting of the cylinder. Has anyone experienced this? Could this be the cause of the ebrake problem?

Probelm #3: As an extension of #2 the "auto adjusting" nature of the rear brakes does not appear to function as indicated in the FSM. Any other thoughts?

Thanks for any tips,

Steve

[Nissanman]

Hmmmm, there is a lot there to address isn't there:rolleyes:

Brake booster: is a feel good device which reduces pedal effort for braking. As a confidence check, disconnect the vacuum hose to the booster [and plug it] and see if the pedal feels any different. That might give you an indication if it is actually boostin'.

BMC: can sometimes be very difficult to bleed properly. However if you don't have a spongy pedal, may be quite OK.

Front pads: check what temperature range they are good at. They may very well be bit too hi-tech for normal driving. Perhaps they need a special bed in procedure too.

E brake: If you have now got all new hardware, perhaps the shoes etc. have been assembled incorrectly. There is something amiss if the adjuster binds on the wheel cylinder. May be wise to carefully check the assembly with the pics. in your FSM to make sure all is well. The shoes definately have to be paired up correctly to have the mechanism work. A stretched e brake cable will make thinks a bit unresponsive as well.

I'm sure you will notice a difference in the braking performance between your Z and BMW, but the Z sounds like it does have an issue somewhere:angry:

[xray]

bump for more help.

As I mentioned before, I have good manifold vacuum, and thebooster holds vacuum within FSM specs...Pedal engagement and feel are normal, except I can't lock the brakes. I suspect I'm not used to the braking system of this car (3 years since driving it) but I don't have an available car for direct comparison.

anyone have some other advice? I'd like not to replace a relatively expensive wheel cylinder unless I have to, so chime in with some help....

Thanks,

Steve

[Neumeier]

Hi!

If your e-brake is not holding, your problem lies with the rear brake shoes. Maybe something is not correct with the hardware. Take of the drum and inspect the shoes. The rear shoe should have its lining up higher than the front shoe, closer to the top, I mean.

Assuming that you have bled everything correctly, and are getting fluid to come out of the rear brake cylinders, its probably not a hydraulic problem.

When adjusting the brakes, periodically push hard on the pedal to recenter the shoes. Also, back off on the e-brake adjustment prior to doing the adjustment using the star wheels. This alone could be the problem. What I mean is that through the years the e-brake was adjusted many times to make up for shoe wear. Upon installing new shoes, you could have more tension on the brake cable than you should.

Another check. See if the shoes fit in the drums correctly. That is, does the shoe curvature match the drum curvature.

Did you lubricate any pivot points? Star wheel threads, points where shoes touch backing plate, and points where shoes touch one ends (at brake cylinder and stationary point.

With regard to the binding you note, and the problems with the self adjuster, they may be different for each side of the car. Look at how the action is to see if both sides could be tightened when the e-brake is actuated.

Finally, there could be a problem with a valve that balances pressure from front to rear. There is one above the rear axle and another one under the master cylinder. I'm not to familiar with these though.

Good luck!

John

[Nissanman]

The 240Z and 260Z had a "pressure regulating valve" and a "dual circuit pressure differential switch".

They are located in different places though, see image.