Hello everyone,
I came across this site and I hope to find some useful information. First off i have a 1996 volvo 850 with 137000 miles. I had some problems with the brakes a while back. My rotors were worn so I replaced them and the pads. Everything was working fine. When I first got the car the abs light was ALWAYS on so I just took out my instrument cluster and took the light out because it annoyed me. My problem is when I stop it feels like it is pulsating. The brake pads feel like they are catching more at certain parts of the rotor. My only guess is that it is the abs. I have been doing research but no one seems to know the solution. Could my abs module have gone bad? I was thinking of just disabling it. Any info on what I should do?

On another note when my car sits up for 3 or 4 days without being cranked it idles very roughly and seems like it wants to shut down. After it gets running for a while though its fine. Any input on that? Thanks alot for reading my post. Any help would be greatly appreciated.

Hello back at you...
:)

If your ABS light is always on, then it's functions are already disabled, until you have it properly taken cared of. But in anycase, bad ABS modules does not mean you no longer can brake in your car. :) The braking functions will continue to function as normal if the module goes bad. Don't worry. Only that there is NO ABS. Meaning, if you want to drop to 0 speed from 100kmh with one strong solid braking on sandy roads or icy or wet roads, well, be prepared for screeeching sounds (and subsequent hit this and that episode...) Hehehe...

Check your rotors again. And check your pads. Did you use new pads with the change in the rotors previously?

If need be, SKIM the rotor surface, and get the pads rubbed a bit to straighten/level the surface if they are still thick. The minimum recommended thickness of the rotors are written on the outside part of the rotor 'hat'... (Might need some cleaning before you can see them, though...)...







Try cleaning the throttle body and the IACV.

BTW, Welcome, Greenpx!

So you don't think it's an ABS problem then? When I replaced the rotors I replaced the pads as well. I scrubbed them on the surface to fix the uneven problem but it still keeps coming back and it just doesn't make any sense at all. Do you have any other suggestions?

Also I am going to sound ignorant but where is the throttle body and the IACV. How do I go about cleaning them? I took it in for the same problem a while back because it was just violently shaking and air was getting in my engine somehow through a hose..not sure how. Ill try cleaning those if you can help me out with where they are..haha. The brakesa re my biggest concern right now though.

Thanks for the welcome. =)

Don't get me wrong... If your ABS has ALWAYS had the light on, then you definitely should have it checked...


:blush:

Apparently, new rotors may still be problematic. If you just changed it, send it back to the shop and ask them to give you a new pair. Warranty should still be in. You can use the pads again...

The IACV is at the front, between the radiator and the engine block. Under the throttle butterfly... It is a lot easier to disassemble, however, the TB needs mechanics' help. Why don't you send it in, and watch the mechanic do the work. Later on, you can do it yourself!
:)

One other famous cause is the MAF sensor...

Do you have a Lambda error light...?

Both the IACV and TB located under here...

Well on the rotors, they aren't volvo brake rotors. Do you think the problem is they are non volvo brake discs? It feels like its just the back rotors that are giving the problem. I put the new aftermarket ones on not that long ago, but Im guessing that may be the problem.

Though not original, some aftermarket ones are really good... so, i wouldn't blame the rotors generally.

However, if you've identified that the back rotors are the ones with the problem, send it back (hopefully warranty is still there) and get them changed... Some shops would skim them for you, for free, instead of replacing them outright. If you can do something about it, demand for a new set.

Hey so you would recommend just replacing the back ones then? I dont have the receipt from the shop at all anymore and I am pretty sure they are out of warranty. I bought the cheapest ones that I could.

Shops that specialises in brakes would be able to tell if the brakes are in good condition or not. From here, i can't tell at all.

Please take it to them, and invest a little more for your safety. Afterall, those brakes are the thing that ensures you can stop in time.

Thanks I think I will just end up replacing the back rotors

Hope it fixes things up for you...