Where is the problem?? *new problem last page*

[turboz34]

Hey guys i did some maitenance on my 92 z34 lumina a week ago and ive been getting F8cked ever since. I noticed my rear calipers were sticking a little bit so i went ahead and replaced the calipers with new pads and rotors. I bled the brakes and i noticed that hey my brakes feel weak as shit now. I bled them again. No change. The next day i take out the master cylinder looks a little worn out but nothing really wrong with it, I go ahead and replace it as well. After bleeding the brakes and the 2 nipples on the master cylinder I find that fixed nothing. Next day after a quick examination of the front calipers one of the pistons in the front left caliper is seized up. I go ahead and replace both of those. So now ive bled the brakes close to 6 times 5 times with my brother the old fashioned way and once with a power bleeder. I'm about to drop the car of at a shop because im so pissed :verymad: . Any ideas? I cant find any leaks and im not losing any fluid, The pedal goes about 80% to the floor before it starts to work very well at all. I'm stumped

[DaveFromColorado]

... sounds like the prop valve is starting to give up on you ... you may want to look into that. Also, if your E-brake works, cycle that a couple times to get the rear pistons up against the rotors, and see if that helps.

 

be warned tho, sometimes the e-brake cable can stick causing too much drag on the rear brakes.

 

--Dave.

[NeonKnight]

prop valve?? could you explain this some more.. my car does this same thing also. and i know my front left caliper has a torn boot but that wouldnt make it as shitty as it is now... so yea i do not know lol.

 

i want to redo the brakes, and do the rear 94+ upgrade.

[DaveFromColorado]

the "prop valve" as I called it is the proportioning valve used to control the ammount of pressure regulated to each of the wheels - if this valve is having issues, it will cause irregular feel, irregular travel, and a general disgusting feel when trying to stop.

 

I'm not 100% sure if all W-body's have this or not, but it'd be something to look into ... I've never had to dive that far into the brakes on any of my W's, as they've always had a good feel, and have stopped me on a dime.

 

--Dave.

[turboz34]

I've been hunting thru my Haynes manual and looking over the car and i cant find a prop valve in either case. I'm pretty sure this car dosent have one. The only other thing i can think of is the booster. I thought that if they went bad i would lose fluid. :?: But to be honest with u, I've been really busy and havent needed to drive the car lately. Sorry about taking so long to get back to you guys.

[Guest TurboSedan]

it has a prop valve, it's just integrated into the master cylinder (meaning you already replaced it).

[DaveFromColorado]

Take your time, there's no rush

 

Yeah, I don't think a Haynes manual would cover the prop valve actually - it's a part that doesn't usually go bad, and requires LOTS of bleeding once you're done replacing it.

 

Do you have ABS? it could* be the valving in that too causing the problem.

 

now if the booster goes bad, you won't always loose fluid - normally fluid loss with a bad booster is caused by a bad master cylinder getting into the booster causing the bladder in there to rot away.

 

Here's a quick question - I've seen this a couple times (and someone just reminded me of it yesterday) if you've got bad brake hoses that are expanding too much, that'd cause a loss of pressure to the calipers which could result in this type of issue as well.

 

just a few more things for ya to look at.

 

--Dave.

[5speedz34]

Have you made sure you put the calipers on the right way?

 

I know it's a stupid question. When I did my 94+ upgrade, we put the calipers on backwards and the bleeders where on the bottom and air rises so, you can't bleed them.

[turboz34]

Good call josh.

Brakes are mounted right.

If the lines r worn out and expanding will i be able to see them expand? or can a very small amount of this happen to all the lines and still cause a problem. Thats next on my list I might as well put new lines on to go with everything else. But if that dosent fix it im throwing in the towel. And I'll let some one else try.

[DaveFromColorado]

if you can see the lines expanding, you're already in trouble.

 

replacing the lines won't hurt anything tho, so I'd recomend it anyhow.

 

--Dave.

[turboz34]

I replaced the lines(hoses) last weekend. I didnt see any major damage to the old lines. I also managed to break a bolt off in the bracket that holds the line in place, on the rear driver side The car still has very weak brakes. I took it to a friend/mechanic the other day. He told me in some cases u have to hook up a scan tool or possibly a lap top to the car and cycle the abs controller on the car to get all the air out. I hope he has more luck than i did. I'll post what he finds.

[DiscoStudd]

If you have ABS, then you will have to cycle the ABS pump to get all of the air bled out of the system, especially seeing as you've replaced the MC...

[birdman]

well you sound like me about three mounths ago, if you want to cycle the abs, stomp the brakes while driving through grass in one of your many feilds, its what i did. but try somthing else also, mine had a bad pedal feel and dont work well but drive around and pump the brakes alot, mabey 10 good hard stops and see if the brakes work better because my car wont stop for shit until the brakes warm up then it stops like new. just an idea. BTW, do you still have the side skirts?

[turboz34]

well i already dropped the car off so ill have to wait and see if that was the prob. Yeah birdman i still have the skirts. [br]Posted on: April 01, 2006, 10:10:50 AM_________________________________________________I got the car back today and it had air in the abs pump. They still feel weak to me, but the car is much more driveable. I have a speed censor out on the driver side which turns on my abs light, so i couldnt have cycled the abs even if i had known. But hey live and learn, next time I'll be sure to check that shit. [br]Posted on: April 03, 2006, 08:00:25 PM_________________________________________________Hey guys i got another problem. The lumina is using the abs now under regular stoppping. Not every time i hit the brakes but when i slow down to 15mph. The pedal will stiffin up and the car will act like its slidding on ice. kicking on and off quickly. When this happens my abs light will not be on and The other day i drove the car i had the abs light on and it seemed to drive normal. My guess is that with a wheel speed sensor not functioning properly, Its causing the the abs to kick on because it thinks the wheel isnt spinning.

So i hooked up a red brick scanner to it and it shows left front tire excessive wheel spin. But while driving the car we noticed that the right rear wheel sensor isnt reading the same as the others. Often more than 10mph, odd huh? Even after clearing the codes this same thing pops up eventually.

Does it sound like im on the right track? How much do wheel speed sensors usually cost?

[birdman]

http://www.partsamerica.com/ProductList.aspx?PartType=1060&PTSet=A&SearchFor=ABS%20Wheel%20Sensor

theres the link for pricing, if that is the case you may try the junkyard because those are kinda pricey. you could alawys unplug the abs until you decide to get the wheel sensors so its not doing funny stuff while your driving.

[turboz34]

Thanks camron, yo did u try to call again the other day?

I think im gonna just remove the abs fuse and sell the car, if i cant find good ones at a junk yard. Im gonna put more money in the car than i can sell it for if my luck keeps up like this.

[birdman]

no i didnt try and call again. yea i hope it works out for ya, if not at least you got the regal.