brake/ ABS/TRCAS fault, groaning noise coming from footwell+no brakes

**no1tosh** · Monday 1st July 2013, 18:54

as the title says, i have been hearing a weird groaning noise coming from the footwell on and off since i took off my dump valve. It has only happened for a second or two until tonight driving home from work where it has done it consistantly. Every time i have applyed the brake it feels very hard, vibrating and very little stopping power. then the ABS and TRACS lights came on and the groaning stopped and the brakes worked.

i switched the car off at my dads, when i came back out and drove off the lights went out and the noise came back for a minute the same again lights came on and the noise stopped.

like i said above the only thing i have changed is i have removed the dump valve and blocked the vac going to the inlet manifold. there is no recirculation system, just the turbo blanking plate. I dont know if this has anything to do with it? maybe a build up of preasure?

oh and ive had a 4 wheel alighment done but that couldn't be it.

please help im at a loss

thank you

**JamesT5** · Monday 1st July 2013, 20:35

Possibly related to the wheel bearing or drive shaft because the reluctor rings are down there somewhere and if they are out of line then it will set the ABS/Tracs fault in motion. Just a thought!

**no1tosh** · Monday 1st July 2013, 21:56

i have read that ya, and also the abs modul. it is strange that when the abs and tracs warning lights are on it doesn't do it. when it is, it's bloody dangerous, no car no getting to work

again iv'e found a few threads on goggle with these simtoms but again it seems they have fixxed it and not bothered putting up the cure!!

**no1tosh** · Monday 1st July 2013, 23:11

Ok may have sussed it, apparantly 96 models had a loom extention from the module to the front abs sensors and where they spliced it under the fuse box and has a bad conection. It seems to be very common.

iv'e read volvo sell an extended loom replacement or you can just re-do the conection. so ill have a go at that tomorrow night.

**nobananas** · Monday 1st July 2013, 23:26

When the abs light comes on the abs is disabled so this would explain why the brakes started behaving when the light was on. Check the loom you're looking at, also the abs module may need resoldering (but that fault usually just puts the abs light on permanently) but also I have had one of the abs rings crack on mine before and 'freewheel' on the c/v joint, have also had a c/v boot clip slide off over the abs ring, both times caused some very weird reactions from the abs system.

**ajc106** · Tuesday 2nd July 2013, 19:49

you will find the abs rings on the cv joints are all rusty and giving a false signal to the sensors you need to replace the cv joints or the rings a quick way to check is to clean the rings on the cv the fault will go away for a while till the rust starts again have had this fault with mine hope this helps

**no1tosh** · Tuesday 2nd July 2013, 20:08

cheers guys, as soon as i get a nice day ill have a look. i pulled the fuse today just to disable the abs.
i have just tryed to get the fuse box out to look for these badly crimped wires and couldn't get the box out. looked under the dash and could even begin to make out which wires it could be lol. i had to give up as the rain started bug time.