brake issue

[dndeans]

Help. I'm having an issue with my rear brakes that I've not seen posted. My ABS light has been on now for about a year. At first this was not a problem or so I thought. Brakes acting normal but new pads were needed so I replaced them all around. About two months later my daughter was driving it to school across the state, and called to say she was having brake problems. Mechanic at her location said that the brakes were shot. He installed new calipers and rotors on rear and pads all around. About one month later daughter reports intermittent noise and a mechanic in her area sees no problem with her brakes. One month later and the daughter is home and still having intermittent problems. I check brakes to find inner pad on right rear completely worn out and rotor worn. When I tried to push the caliper piston back in it was very stiff. At first it moved ok but then stiffened up as if the return line was plugged. Is it likely that my abs system (with the fuse out) is valving off the return brake line? Does the abs module referred to in previous post include the valving or is it just the electrical part? Any other suggestions to fix this not so intermittent problem now?

[SlowPro48]

Had this happen on my truck a few years ago. Took a while to figure it out. Turned out to be the brake line. They have two layers and the inner layer developed a tear. The resulting flap of rubber acted as a check valve that prevented brake fluid from flowing back out of the caliper when I let off the brakes, so that one caliper was dragging all the time. Might want to replace the brake line and see if that helps.

[VxSport]

Just a quick thought.... check the slider pins on the Calipers too.... I know your mechanic should have greased them too.
I wonder if you could check the brake lines with Vac pump on each end of the brake line.... to see if it won't flo both ways evenly.
keep us informed

[chadzu]

when I bought my vx this summer I went over the brakes first thing. I found that 3 of the 4 calipers had badly corroded pins, and one rear actually had a pin broken off and was just being held on by a little stub. I replaced all the pins and the caliper brackets with good used trooper parts and it make a big difference.
I think many times a mechanic only pulls the bottom pin and rotates the caliper up to insert new pads. This can lead to seizure because they never get properly cleaned and greased.

[tom4bren]

X2 on what they said.

It's the opportune time to upgrade to Stainless Steel brake lines & a GOOD brake job. The SS brake lines are probably going to be cheaper than OEM so that's a no-brainer. You'll lose all of your brake fluid during the install of new lines ... but that's a good thing. If your brake lines have been compromised, the fluid may be contaminated. Just be fore-warned, bleeding your brakes after refilling is CRITICAL and difficult by yourself. Plan on having a helper available for that part. While you are in the process of replacing the pads, you'll see what parts have to be able to slide & which ones are stationary. Anything that slides should be cleaned and lubricated.

If your rotor is scored & is too far gone to just be turned, you may want to check into cross drilled rotors. Rumor has it that it can improve the braking performance (I'm still running the original rotors so I can't verify that for you).

There are plenty of threads on SS brake lines & cross drilled rotors so use the search function on the home page to find them. It'll help save you quite a bit of on line research trying to source parts. Additionally, the better informed you are, the better you'll be able to work with your mechanic in the future to diagnose the issue.

[dndeans]

All moving parts are in great shape and slide easily. Caliper piston won't fully retract. The vacuum pump test sounds promising for checking the hoses. Do I connect to the bleed valve to extend the piston, then remove the hose and apply vacuum to the end of the hose? I would think that if upon removing the hose, the piston would still resist moving would be an indication that the hose was bad. If on the other hand the piston moved freely, that would indicate that the problem was further upstream than that hose. I've been reading the workshop manual and found that the master cylinder could be a suspect. I'll probably start by changing the hoses first anyway. Does anyone think that the abs control unit could be the problem?

[tom4bren]

Does anyone think that the abs control unit could be the problem?

Not likely ... but anything is possible.

ABS modules are intentionally designed to NOT degrade braking performance if the unit fails.

My best guess is that you have a bad caliper. Second choice would be the lines (solely based on post #2). Master cylendar isn't high on my probability list since it serves all 4 brakes & only 1 is affected.

[SlowPro48]

Nah, you don't need to mess with a vacuum pump. Results would not be definitive anyway since air might sneak past a restriction in the line a lot quicker than viscous brake fluid would, thus yielding a false negative. The simple way to test this would be to have a helper apply the brakes and then release them. Shortly after the brakes are released, you crack open the bleed valve on the caliper in question. If fluid sprays out under pressure, you know you have a fluid return problem - either in a rubber line or at the master cylinder. More than likely the line. The only times I've seen a MC cause this problem was after a rebuild using out of spec cups that covered the return hole or else using a drum brake MC for disks - and like Tom pointed out - you would have more than one caliper involved if the MC were causing the problem.

If fluid just dribbles out via force of gravity then you know the problem is with the caliper itself. Hopefully the latter is the case since calipers and pads are new. Caliper surely would be replaced under warranty and you could probably shame the supplier into replacing pads & rotor too since the defective caliper is what trashed them.

If it does turn out to be the flexible line, it's not a huge deal money-wise and like Tom said - a good chance to upgrade to SS lines which will give you better feel when braking. Make sure you get a five line kit with real stainless steel not Kevlar - it's strong but not nearly as abrasion resistant as SS - and you definitely don't want the ones wrapped in SS-colored plastic - they're just for looks. Goodridge is a brand you can trust. There are probably others but I don't have any experience with them. Never used anything but Goodridge.

And no, it's not your ABS causing this. BTW, did you know you can get your ABS unit repaired for less than $100?

[dndeans]

Problem was simply the "new" caliper. I wanted to assume that since it was replaced by a "real" mechanic it had to be OK. I replaced the caliper along with the outer brake lines and at least for now, no sticking brakes. As for the abs module, Ive seen e-bay vendors mentioned as repair shops, but can't find one who lists the vx unit specifically. Which vendor are others using?

[Ldub]

Ive seen e-bay vendors mentioned as repair shops, but can't find one who lists the vx unit specifically. Which vendor are others using?

http://www.vehicross.info/forums/showpost.php?p=267217&postcount=54

OR...look here...:smilewink

http://stores.shop.ebay.com/_si.html?_nkw=ABS+module+repair&_trksid=p4506.c0.m57

[tom4bren]

Problem was simply the "new" caliper. I wanted to assume that since it was replaced by a "real" mechanic it had to be OK. I replaced the caliper along with the outer brake lines and at least for now, no sticking brakes. As for the abs module, Ive seen e-bay vendors mentioned as repair shops, but can't find one who lists the vx unit specifically. Which vendor are others using?

Looks like it's time for me to take this plunge. I've replaced the RR pads twice in a year & they're shot again.

The slide pins are cleaned & lubed each time so I'm pretty sure the pistons in the caliper are binding. I've run them through the entire throw several times each time I replace the pads & they are kinda hard to compress even though they do move the entire travel.

The rotor is kinda scored too so that'll have to be replaced at the same time (I'm sure it's too far gone to just get it turned).

Since I'll be opening the system, now would be the perfect time to upgrade to SS lines.

Does anyone know of any complete kits available or should I just shop around for the parts?

[MSHardeman]

Tom,

Independent 4X has a full stainless steel brake line kit for us:

http://www.independent4x.com/Isuzu-Braided-Steel-Brake-Line-Set_p_21.html

I bought this kit a few years ago, put it on and haven't had a problem since.

I would cautions you, though, not to do what I did and leave the system open for a few days. :( I took everything off, and apart, and painted the calipers. The system sat open for a couple of days while I got the calipers painted and dried and when I put it all back together the brakes never felt quite right. Come to find out my master cylinder decided to give up the ghost and I had to replace it. Now, I don't know if it was going out anyway, or if leaving the system open that long dried some stuff out and ruined it.

[tom4bren]

Do you remember how much you paid at Indy?

The Goodridge site lists them for $156

http://1653468.r.msn.com/?ld=8v9io9H6j4fr3zkUFJmfqiUjVUCUwnhEz4XD69D6gLHzqi C0dl6sLZJ0T3qUx-3-hglcaAXjMQnxcxPgIBVXrSYKB8Eeaxwb0Zdl-C4_O9g9jD_Iwe6n44cO5fC8IMA6RfIkIOullutjFi_o4Aw9BJa Ko8M2o&u=http%3a%2f%2fwww.buybrakes.com%2fp-679-goodridge-g-stop-brake-line-kit.aspx%3futm_source%3dBing%26utm_medium%3dPPC%26 utm_campaign%3dBrakeLines

Never mind, found it: $180

http://www.independent4x.com/Isuzu-Braided-Steel-Brake-Line-Set_p_21.html

IIRC, the Indy's are made for a 3" lift whilst the Goodridge are advertised as OEM.

[MSHardeman]

I think I paid about $150 four or five years ago.