Shaking Steering

turboboy · Apr 12th, 2006, 08:30

My 740 Estate only gets used occasionally (for collecting large items and trips to get rid of household/garden waste etc.) but always seems to perform, on most occasions, smoothly and flawlessly.

A couple of years ago I had a sticking rear caliper which boiled the brake fluid on a trip to deepest Norfolk - if you have never driven a car with no brakes then you do not know what panic is!!!!

Anyway, last night I drove down the M3 and on to the car park (aka M25) and crawled along, stop start, for I guess 10 miles never moving at more than about walking pace. I should add that as it has an auto gearbox I was constantly on the brakes.

On reaching the M40 turn off I accellerated and got up to 60+ MPH and drove without problem for about a couple of miles when the steering started to shake. This became more violent and I thought that I had perhaps had a puncture or a balance weight had fallen off. I stopped and checked but everything appeared OK.

Pulling away seemed OK but the shaking returned within about half a mile.

I found that stopping and letting the car cool down got rid of the shaking and eventually, after a prolonged "rest" the problem went away completely.

What I did also notice that the N/S front brake disk seemed hotter than the O/S and that in the stop start conditions the brakes started to pull towards the O/S.

I think this points to a sticking front caliper, but if this is the case why did the steering shake so much (as if the disk had a lump at one position)?

Has anyone experienced this before or have any suggestions on what may be the problem. Thanks

James_N · Apr 12th, 2006, 10:51

was gonna say it could be a wheel balancing problem, maybe you need them balanced but from the last bit of your explanation, it sounds more mysterious.

Apr 12th, 2006, 12:20

Sounds like some sort of sticking brakes problem... maybe disc runout is excessive on that side too. When it is in "non-shake" mode try hard braking and if the steering shakes then that's pointing you to the problem. Check out the caliper, have pads out and clean it all up then see how it goes. In old car of mine I once had a SEIZED caliper which was absolutely fine once you let the car cool off. Lets hope you get away with not needing a new caliper, I did I just cleaned it all lubricated and it was ok... but I never, ever felt confident using those brakes again then got rid of the car

Cheers, Pete

ivor940 · Apr 13th, 2006, 10:24

Hi, the 940 front calipers are known to seize either at the slide pins under the rubber boots, or the metal to metal contact area where the actual caliper slides on the mount frame.

ivor940

turboboy · Apr 13th, 2006, 19:45

Thanks for the reply fellers. I'm glad that everyone so far has agreed that it seems to be sticking calliper.

I'm hoping that if I take it off and clean and lubricate the caliper and mounting it will solve the problem. The strange part is that once it had "rested" the car ran as smooth as the proverbial young persons posterior.

I forgot to mention in my original post that the front calipers are Bendix (if that has any relevance?). Also I don't think I have ABS (its an '88 740 Turbo) so a fault in that can be eliminated.

As an aside, my son said "Oh yes, that happened to me when I used the Volvo the other week, but because it resolved itself I forget to mention it". Thanks Son!

Peter Milnes · Apr 14th, 2006, 00:47

It is possible that you may have ABS. To check look under the boot floor at right hand side. Acouple of units and a load of hydraulic piping will tell you that you have, absence states you haven't unless it is mounted under the bonnet by the lefthand strut tower.

All the best, Peter.

John Davies · Apr 14th, 2006, 01:14

Hi
I had a similar problem on a 240. Cost me a new caliper to sort out.

When brake discs are machined they normally have a slightly 'high' spot on them to throw the pads off when not braking.

If the pistons sieze in the caliper, or to a lesser extent the pads on the pins, then you can get the problem you mention as the 'high spot' passes the pads once the brakes are hot.

There may well be other possible causes, but the key is that you say the problem is better when things are allowed to cool off.

I would check both front calipers - if you need to replace pads you will need to do both sides anyway.

The other cause is a fault on the ABS if you have it, but check the easy options first!

John Davies

Apr 12th, 2006, 08:30	#1
turboboy Master Member Last Online: Dec 15th, 2023 08:44 Join Date: Dec 2003 Location: Twickenham	Shaking Steering My 740 Estate only gets used occasionally (for collecting large items and trips to get rid of household/garden waste etc.) but always seems to perform, on most occasions, smoothly and flawlessly. A couple of years ago I had a sticking rear caliper which boiled the brake fluid on a trip to deepest Norfolk - if you have never driven a car with no brakes then you do not know what panic is!!!! Anyway, last night I drove down the M3 and on to the car park (aka M25) and crawled along, stop start, for I guess 10 miles never moving at more than about walking pace. I should add that as it has an auto gearbox I was constantly on the brakes. On reaching the M40 turn off I accellerated and got up to 60+ MPH and drove without problem for about a couple of miles when the steering started to shake. This became more violent and I thought that I had perhaps had a puncture or a balance weight had fallen off. I stopped and checked but everything appeared OK. Pulling away seemed OK but the shaking returned within about half a mile. I found that stopping and letting the car cool down got rid of the shaking and eventually, after a prolonged "rest" the problem went away completely. What I did also notice that the N/S front brake disk seemed hotter than the O/S and that in the stop start conditions the brakes started to pull towards the O/S. I think this points to a sticking front caliper, but if this is the case why did the steering shake so much (as if the disk had a lump at one position)? Has anyone experienced this before or have any suggestions on what may be the problem. Thanks

Apr 12th, 2006, 10:51	#2
James_N VOC Member Last Online: Jan 4th, 2024 11:32 Join Date: Jan 2006 Location: Stafford View Photos By: James_N	was gonna say it could be a wheel balancing problem, maybe you need them balanced but from the last bit of your explanation, it sounds more mysterious. __________________ 1997 Volvo 940 LPT Celebration. 187,700 miles, manual.

Apr 14th, 2006, 01:14	#7
John Davies VOC Member Last Online: Sep 26th, 2015 22:56 Join Date: Dec 2002 Location: Walsall	Hi I had a similar problem on a 240. Cost me a new caliper to sort out. When brake discs are machined they normally have a slightly 'high' spot on them to throw the pads off when not braking. If the pistons sieze in the caliper, or to a lesser extent the pads on the pins, then you can get the problem you mention as the 'high spot' passes the pads once the brakes are hot. There may well be other possible causes, but the key is that you say the problem is better when things are allowed to cool off. I would check both front calipers - if you need to replace pads you will need to do both sides anyway. The other cause is a fault on the ABS if you have it, but check the easy options first! John Davies __________________ Volvo 760 GLE turbodiesel estate 1989 (auto). Ford Mondeo 2001 mk. 3 Ghia X petrol estate. Austin A60 Cambridge 1966 (auto) . Austin A60 Cambridge 1967 (manual) undergoing restoration.

Apr 12th, 2006, 12:20	#3
peteS40 Guest Location:	Sounds like some sort of sticking brakes problem... maybe disc runout is excessive on that side too. When it is in "non-shake" mode try hard braking and if the steering shakes then that's pointing you to the problem. Check out the caliper, have pads out and clean it all up then see how it goes. In old car of mine I once had a SEIZED caliper which was absolutely fine once you let the car cool off. Lets hope you get away with not needing a new caliper, I did I just cleaned it all lubricated and it was ok... but I never, ever felt confident using those brakes again then got rid of the car Cheers, Pete

Apr 13th, 2006, 10:24	#4
ivor940 Master Member Last Online: Sep 16th, 2013 07:55 Join Date: Dec 2003 Location: Malahide View Photos By: ivor940	Hi, the 940 front calipers are known to seize either at the slide pins under the rubber boots, or the metal to metal contact area where the actual caliper slides on the mount frame. ivor940

Apr 13th, 2006, 19:45	#5
turboboy Master Member Last Online: Dec 15th, 2023 08:44 Join Date: Dec 2003 Location: Twickenham	Thanks for the reply fellers. I'm glad that everyone so far has agreed that it seems to be sticking calliper. I'm hoping that if I take it off and clean and lubricate the caliper and mounting it will solve the problem. The strange part is that once it had "rested" the car ran as smooth as the proverbial young persons posterior. I forgot to mention in my original post that the front calipers are Bendix (if that has any relevance?). Also I don't think I have ABS (its an '88 740 Turbo) so a fault in that can be eliminated. As an aside, my son said "Oh yes, that happened to me when I used the Volvo the other week, but because it resolved itself I forget to mention it". Thanks Son!

Apr 14th, 2006, 00:47	#6
Peter Milnes Premier Member Last Online: Apr 10th, 2014 00:01 Join Date: Feb 2002 Location: Tonyrefail	It is possible that you may have ABS. To check look under the boot floor at right hand side. Acouple of units and a load of hydraulic piping will tell you that you have, absence states you haven't unless it is mounted under the bonnet by the lefthand strut tower. All the best, Peter.

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