Dragging sound, Diff?

Steve Curtis · Dec 6th, 2010, 11:57

Hello all.

After my 800 mile drive Through serious German snow, Belgian rain and Kentish slush. I now have some issues with my 945.

Its a 945 Turbo Sport.

I am getting a sought of dragging sound/sensation from (I think) the rear of my car. It Only seems to happen if I pull off hard in first or second. Its a sought of graunching sound.

My old 240 also makes this noise but only when its got a lot of weight in the back. just incase that through's any more light on the subject.

The only other thing I noticed a couple of times is that when pulling over at a service station I was detecting the aroma of burning clutch????

Any ideas???

Steve Curtis · Dec 7th, 2010, 17:03

Ok so today there is no sign of the dragging noise.

It seems to be related to weight and distance. I reckon if I put some weight of the rear I could provoke it. I start to wounder if this is tied into my other issue with my brakes not clearing properly. Is there some kind of brake bias valve i the system that has maybe become in operative. When full of weight it might force it to work a little and then stick on when stopping.

I know this is a common problem with retro VW cars

Any ideas?

gpl1968 · Dec 7th, 2010, 18:52

From the oracle that is Vadis:
"Cars with ABS and models without ABS from 1992 on are equipped with an axle-split braking system. In this case, the rear circuit supplies the front brakes and the front circuit the rear brakes. The purpose of the reducing valve (which was added to the rear brakes on 1992 models) is to reduce the pressure in the rear circuit under severe braking conditions to prevent wheel lock.
The reducing valve incorporates a safety function which is associated with the front brakes. In the event of an hydraulic fault in the front brakes, the pressure to the rear brakes is maintained at its full, unreduced value."

Steve Curtis · Dec 7th, 2010, 23:00

What is Vadis out of curiosity?

Any idea where this reducing valve might be located? Sounds promising especially if it turns out to be a mechanical part?

gpl1968 · Dec 7th, 2010, 23:41

Volvo Aftersales Diagnostics and Information System.
Volvo garages used it before 2005. Bootleg versions are available widely on the likes of ebay for a few pounds.
Its main use is as a parts list for models from the 240 through to 2005 with servicing instructions for the 940 and later.

The reducing valve is mounted on the firewall below the master cylinder.

Dec 6th, 2010, 11:57	#1
Steve Curtis super cruising 240 Last Online: Jul 3rd, 2018 21:35 Join Date: Oct 2004 Location: Swindon	Dragging sound, Diff? Hello all. After my 800 mile drive Through serious German snow, Belgian rain and Kentish slush. I now have some issues with my 945. Its a 945 Turbo Sport. I am getting a sought of dragging sound/sensation from (I think) the rear of my car. It Only seems to happen if I pull off hard in first or second. Its a sought of graunching sound. My old 240 also makes this noise but only when its got a lot of weight in the back. just incase that through's any more light on the subject. The only other thing I noticed a couple of times is that when pulling over at a service station I was detecting the aroma of burning clutch???? Any ideas??? __________________

Dec 7th, 2010, 17:03	#2
Steve Curtis super cruising 240 Last Online: Jul 3rd, 2018 21:35 Join Date: Oct 2004 Location: Swindon	Ok so today there is no sign of the dragging noise. It seems to be related to weight and distance. I reckon if I put some weight of the rear I could provoke it. I start to wounder if this is tied into my other issue with my brakes not clearing properly. Is there some kind of brake bias valve i the system that has maybe become in operative. When full of weight it might force it to work a little and then stick on when stopping. I know this is a common problem with retro VW cars Any ideas? __________________

Dec 7th, 2010, 18:52	#3
gpl1968 VOC Member Last Online: May 5th, 2024 23:42 Join Date: Jun 2007 Location: Wirral View Photos By: gpl1968	From the oracle that is Vadis: "Cars with ABS and models without ABS from 1992 on are equipped with an axle-split braking system. In this case, the rear circuit supplies the front brakes and the front circuit the rear brakes. The purpose of the reducing valve (which was added to the rear brakes on 1992 models) is to reduce the pressure in the rear circuit under severe braking conditions to prevent wheel lock. The reducing valve incorporates a safety function which is associated with the front brakes. In the event of an hydraulic fault in the front brakes, the pressure to the rear brakes is maintained at its full, unreduced value." __________________ Gavin 1997 945 CD (B230FK) [RIP: 1991 945 Turbo (B230FT) 1992 945 SE turbo (B200FT)]

Dec 7th, 2010, 23:00	#4
Steve Curtis super cruising 240 Last Online: Jul 3rd, 2018 21:35 Join Date: Oct 2004 Location: Swindon	What is Vadis out of curiosity? Any idea where this reducing valve might be located? Sounds promising especially if it turns out to be a mechanical part? __________________

Dec 7th, 2010, 23:41	#5
gpl1968 VOC Member Last Online: May 5th, 2024 23:42 Join Date: Jun 2007 Location: Wirral View Photos By: gpl1968	Volvo Aftersales Diagnostics and Information System. Volvo garages used it before 2005. Bootleg versions are available widely on the likes of ebay for a few pounds. Its main use is as a parts list for models from the 240 through to 2005 with servicing instructions for the 940 and later. The reducing valve is mounted on the firewall below the master cylinder. __________________ Gavin 1997 945 CD (B230FK) [RIP: 1991 945 Turbo (B230FT) 1992 945 SE turbo (B200FT)]

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