Offside brake binding but drifting left?

[ilmiont]

At this point I'm quite sure the front offside brake is lightly binding but the car is drifting to the left.

This began - was first noticed anyway - a couple of weeks ago. After a motorway run the front offside wheel was noticeably much hotter than the nearside. The pad wear is excessive: approaching 5mm on the offside outer, compared with 8mm on the nearside outer. I suspect given that level of wear it's been doing this for a while but as I rarely run at motorway speeds for an extended time it's not generated enough heat to attract my attention.

I stripped and cleaned the brakes last weekend. The slide pins were heavily contaminated and the caliper was quite stuck around the pads. I greased the pad/carrier contact points and the slide pins with silicon grease. Once I'd finished it all seemed to move freely.

Yesterday I was planning a trip up north - drop into the Northern BKV and then to a family friend - but the drifting returned after about 40 miles (mostly 70mph, overall average speed had reached 56mph from home) and sure enough the front offside wheel smelt hot and was throwing off significant heat while the nearside was only warm (engine braking + very light brake application to get into a layby). I don't think it's really bad, I could still hold the wheel for several seconds, but the difference was unambiguous again this time.

So the bind's still there so I suppose it's new caliper time. But what I don't understand is why the car is drifting left. Shouldn't a constant braking force on a wheel, in this case the offside, cause the rest of the car to effectively pivot around it - creating a drift towards the right in this case? I can't reason through what I'm experiencing.

Current alignment (only a few days ago):

Front Camber: -1.12 / -0.42
Front Toe: 0.04 / 0.04
Rear Toe: 0.04 / 0.03
Rear Camber: -0.11 / 0.03

Not perfect but I can think I can rule out alignment as the cause of the drift - this was just a free check ahead of the long trip but they did end up evening out the front toe for free (it was 0.01 / -0.06 to begin with).

So please can anyone explain why an offside binding brake seems to be causing a drift to the left when not braking. I'm not noticing any significant change on applying the brakes. Am I mad or is this not as it seems.

In the end I aborted the run up north deciding it unwise to continue for another 400 miles, almost all of it on motorways and dual carriageways.

[XC90Mk1]

Originally Posted by ilmiont

At this point I'm quite sure the front offside brake is lightly binding but the car is drifting to the left.

This began - was first noticed anyway - a couple of weeks ago. After a motorway run the front offside wheel was noticeably much hotter than the nearside. The pad wear is excessive: approaching 5mm on the offside outer, compared with 8mm on the nearside outer. I suspect given that level of wear it's been doing this for a while but as I rarely run at motorway speeds for an extended time it's not generated enough heat to attract my attention.

I stripped and cleaned the brakes last weekend. The slide pins were heavily contaminated and the caliper was quite stuck around the pads. I greased the pad/carrier contact points and the slide pins with silicon grease. Once I'd finished it all seemed to move freely.

Yesterday I was planning a trip up north - drop into the Northern BKV and then to a family friend - but the drifting returned after about 40 miles and sure enough the front offside wheel smelt hot and was throwing off significant heat while the nearside was only warm (engine braking + very light brake application to get into a layby). I don't think it's really bad, I could still hold the wheel for several seconds, but the difference was unambiguous again this time.

So the bind's still there so I suppose it's new caliper time. But what I don't understand is why the car is drifting left. Shouldn't a constant braking force on a wheel, in this case the offside, cause the rest of the car to effectively pivot around it - creating a drift towards the right in this case? I can't reason through what I'm experiencing.

Current alignment (only a few days ago):

Front Camber: -1.12 / -0.42
Front Toe: 0.04 / 0.04
Rear Toe: 0.04 / 0.03
Rear Camber: -0.11 / 0.03

Not perfect but I can think I can rule out alignment as the cause of the drift - this was just a free check ahead of the long trip but they did end up evening out the front toe for free (it was 0.01 / -0.06 to begin with).

So please can anyone explain why an offside binding brake seems to be causing a drift to the left when not braking. I'm not noticing any significant change on applying the brakes. Am I mad or is this not as it seems.

In the end I aborted the run up north deciding it unwise to continue for another 400 miles, almost all of it on motorways and dual carriageways.

I can’t explain why it tilts left with an offside binding caliper.

However… I recently had excessive binding on the rear offside. The pad and disc stank! After a couple of miles and the entire wheel got hot. Mpg dropped and I had to replace it as soon as possible.

I attempted to degrease slide pins, stripped down etc to no avail. The point is however that even with excessive binding I experienced abosolutly nothing untoward and no moving to the right. I think your main issue is simply your caliper.

[MDS40]

Could this be connected to your other fault in another post about inner tie rod boot failure ?.
Just a thought.

[VolvoRoyS]

Might be uneven tyre wear. Other point is if hub is getting hot then so is the disc which can lead to a warped disc so best to get that caliper changed asap or rebuild it.

Roy

[ilmiont]

The front tyres are slightly unevenly worn, more so on the nearside by 0.1mm - 0.2mm. The fronts have 4,000 miles on them, new in April. Both tyres are worn more on the inner edge. They're Michelin Pilot Sport 5. Around 6.0mm remaining on the offside, about 5.8mm on the nearside at the inner edge. I've noted this wear pattern over several months though - it was certainly the same trend when I measured them back in early June for instance, when the car was driving very well.

I had to use the car on a couple of short trips last week. Same symptoms. The drift may be getting worse and I've noted there's a degree of bump steer appearing too. This is all new; the handling does seem to have deteriorated rather rapidly. Maybe it's related to the brake, maybe not.

The brake is still binding but on last week's gentle trips the heat difference could only be felt by touching the caliper housing - offside too hot to hold after a couple of seconds, nearside comfortable indefinitely. I'm not planning to use the car again now until it's all sorted.

I keep going around in circles trying to work out what to do. I want to do the caliper myself really but I think I should change the hose too, seeing as it's probably the original, and I'm scared about separating the hard line. Also the caliper carrier bolts which I failed to get off a fortnight ago.

The trouble is that with 3 cars in the household, a narrow one-car driveway, and very limited parking elsewhere, resolving things is not as straightforward as just get the jack out again. I can't have the car being immobile for more than a day or so. And it's not just the brake; I've got to do the tie rods too, which look a bit intimidating, and then another alignment.

I am thinking this might just end up with me falling back to "typical car owner" and asking a specialist to "fix it please" and hand her back to me with a non-binding brake and straight tracking. I'm increasingly uncomfortable with some aspects of the place I have been using though - while they now know me and the car, are knowledgeable, friendly, and extremely fair on the bill, organisation and attention to detail isn't always their strength, which concerns me.

I called Horton Cars this afternoon which at 22 miles away is inconvenient but they're very well reviewed, with the bonus of being a Volvo specialist that does wheel alignment in-house. I was rather dismayed though - they point blank refused to fit my own parts, even though they'd all be Genuine Volvo. I thoroughly understand their position (warranty) but the bits I'd buy from FRF would be just the same as what they'd supply themselves.

They wanted £70 for pads, £71 each for discs, and £180 for a caliper - excluding VAT. I don't have a quote from FRF yet but I think being brake bits it could be up to a 40% discount. (There's an eBay seller, swedishcaraccessories which seems to map back to Squire Furneaux Volvo, offering a pair of genuine 305mm discs and pads for £125 all-in at the moment.) I can't really justify paying Horton £130 more for exactly the same thing, even if they do offer a more polished service than I've had elsewhere. There's also 45 miles of petrol to get over there and back, and 45 miles of petrol in one of their cars to get home during the day, so I think they're ruled out really.

The options are probably back to try it myself or trust D&A Autos in Witney to do the job - who will fit owner-supplied Genuine parts without a quibble, but have not always done past jobs quite to my satisfaction. Just silly little things overlooked.

How I wish I had my own garage where I could keep her immobile for days if need be... but I need to keep saving and dreaming for now.

[john493]

Like most garages, Horton will want their mark-up on the parts they fit to your car, regardless of the warranty question.

Although I do all my own work, I can recommend Lewis Motors in Kidlington (behind Kings Two Wheel Centre).
Most likely you have rusted caliper pistons - rather than buy replacement calipers, try rebuilt kits from BiggRed they are good value including a new piston. Rebuilding calipers is not difficult, the worst part is cleaning up the caliper body.

Most garages won't be interested in rebuilding calipers, they'll just want to fit new ones; hence higher parts prices but reduced labour charges (in theory).

You don't need to remove the caliper brackets, just remove the slider bolts with a 7mm allen key.

[VolvoRoyS]

Originally Posted by john493

Most garages won't be interested in rebuilding calipers, they'll just want to fit new ones; hence higher parts prices but reduced labour charges (in theory).

It's not worth their while trying to rebuild a caliper as it may well end up costing the customer more. But for an owner it is definitely worthwhile and a lot cheaper. You probably don't need new discs nor pads. So could be a cheap job if you feel confident in rebuilding a caliper. Rebuild kit (without new piston) can be less than £10.


Roy

[V70roma]

(Had identical problem about 3 months ago , occasionally nearside rear would get very hot and also occasionally juddering around 50 to 70 mph , I noticed the juddering before I found it was getting hot. I took a punt on an eBay pattern part caliper £27.99 fitted it and 3 month later all good shuddering gone and no longer getting hot. I also purchased a rebuild kit from Bigg red for about £8 just in case I every get around to rebuilding the original or if the pattern part fails. Vehicle is 2004 v70 d5 163hp manual.
As others have advised also checked handbrake shoes for delamination.)

I posted the above back in March, the pattern part is still fine after 8 months and Bigg red rebuild kit and original caliper still in shed just in case I get motivated enough to rebuild it.

[ilmiont]

Originally Posted by john493

Like most garages, Horton will want their mark-up on the parts they fit to your car, regardless of the warranty question.

It turns out Horton are not marking up parts. FRF quoted me identical retail prices today, but the forum discount creates huge savings on the final bill.

Originally Posted by VolvoRoyS

It's not worth their while trying to rebuild a caliper as it may well end up costing the customer more. But for an owner it is definitely worthwhile and a lot cheaper. You probably don't need new discs nor pads. So could be a cheap job if you feel confident in rebuilding a caliper. Rebuild kit (without new piston) can be less than £10. Roy

Thank you but I definitely don't feel confident rebuilding a caliper (don't know what's involved) and I think it would add time to the job for me.

Originally Posted by VolvoRoyS

You probably don't need new discs nor pads.

In my unqualified view the pads may as well be changed now, as the nearside have 8mm whilst the offside is down to 5mm with a 1mm taper on the inner pad. Not low by any stretch but uneven enough that I want to change them.

I've decided to buy new genuine calipers, hoses, discs, and pads. I know there's a valid view I could probably change the offside caliper only at this point but I feel more comfortable overhauling everything now and hopefully not having to revisit the front brakes for a long time to come. The nearside caliper is older and it would be just my luck at the moment to have it start binding immediately after the offside has been dealt with. Everything's currently aftermarket parts from the previous owner. I wouldn't necessarily take this approach again in the future, starting with genuine calipers/discs/pads, but have decided now is as good a time as any to restore the baseline. Might be foolish but gives me greater piece of mind.

I've started soaking the unions between the flexible and steel lines with penetrant; hopefully they'll move by the weekend. If they don't, I'll be prepared to abandon and call the garage.

I'm going to make an attempt on the tie rods too. Hopefully after all this and another alignment, the leftward drift will be gone...

[MDS40]

Probably a good idea to get new carrier bolts as you had trouble undoing the previously.
I had and issue with these on my S40 and needed a special socket to loosen them.