My dad was driving my car today to get tires on it for me, he said driving along and all of a sudden a huge vibration through out the whole car came for about 2 seconds then it was gone, he said it scared the *** out of him and hes made of iron and bullets, lol. Any ideas?

Ok, it did it on me today for the first time. The vibration was hard and lasted 2 seconds while braking down a very small hill. It felt like either underneath or in the rear end to me.

HEHE.

I think I know what it was.
But i cant be sure yet for now.

If i am right, its your ABS brake sensors acting up. I dont know WHY i got really loud, but it has happened to me before, and after cleaning the sensors, they were gone.

The hints that gaev this up was:-
1) Loud VIBRATION from underneath the car
2) Lasted just a short time
3) Happens mostly while braking, though it can act-up while in full motion.

Ok, so what clean them with carb and brake cleaner, and they are right above the rotor? I am almost positive its coming from the rear, and my ABS light is on, but its been on a long time.

Well, if the ABS light is permanently on, you may want to read the codes first and see what it says. Then delete the code, before you start work.

But if its intermittent light, chances are that the sensors are the trouble. Use degreasers if you can, they are stronger.

:)

what socket for abs codes?

Dude,

I seriously dont know. You need to check the site for that. I'm on OBD2, and though i try to read on this, without the actual PRACTICE, it just fades away...

I cleaned the rear ones. They were absolutely dirty, and totally covered up. Girlfriend drove the car and she said it still did it. Now not only the srs light is on the ABS light flicked on for about 1 minute. Any suggestions?

Have you read the codes for the ABS yet?
Or is that the one that doesnt register any errors, but still have the error light on?

I'd move to clean the front ones too, as well.
And maybe just check the rear ones to see what made them oily in the first place.

Its gonna have to wait till Monday at the earliest. Tiz ok though, always have old reliable to drive to work.

OK then, dude.

Cheers.

wait wait wai, I had the same problem but I'm a little bamboozled. What's all this talk about checking codes? And how do you clean the abs sensors? Pop the wheels off and just wipe them off?

He has an OBD1 system, which means he can read and delete the codes himself. You didnt say which year your car is manufactured in.

In anycase, what do you mean by "Pop the wheels off and just wipe them off?"

Run a search in this forum, i have posted a photo of where the ABS sensor is located at each wheel. It shouldnt be that difficult to find, its the only sensor with a wire coming out of it. Unscrew it out, and give it a good cleaning, using a degreser or a carb-cleaner etc.

I will go further on that. You take a screw out then it pops straight out.

You should try to clean the sensors for the ABS. They will get dusty/rusty and all crudded up and pop error codes.

You need to pull off the wheels... The sensors are located at the top of the spindle. You can follow the wire going to it to locate it. The wiring connector plugs straight down onto the sensor. Mine had a pretty snug fit. Once the connector is off you can remove the screw. The sensor can now be removed. It is a sealed unit and the grime and metal filings can be wiped off. You might want to take a wire brush to the abs sensor ring also; the ABS ring has small square-ish teeth on it and gets cruddy too and will add to the errors I imagine. The rear wheel are similar.

this link will help you get the codes and erase them when you're done.

http://volvospeed.com/Repair/a3.html
the attached pic is what a new sensor looks like, mine were pretty ugly, but they are still working!

Good luck!

Thank you.

I don't have any brake/abs warning lights coming up and I don't have any error codes showing up. I have a 1996 850. And what I meant by "popping the wheels off and wipe them off" is removing the wheels and wiping the sensors clean. And where do these codes come up at? And thanks for the tips. I'm probably going to rotate the tires soon so I'll probably clean off the abs sensors then.