Investigated brake judder, opinions sought please!

[wafter]

Beware that th penetrating oil may have some solvents which are incompatible with the caliper piston seals!

Thanks - tbh this is only a "quick" test to see if freeing things up resolves the issue. If I do get an improvement I'm probably looking at a new / recon caliper anyway.

 

[wafter]

Well, that was disappointing - having just chucked another couple of hours at it, but found it's no better.

First off were the D/side wheel and caliper, with copious amounts of penetrating oil squirted in behind the dust seal around the piston. I did notice that it was weeping a little, however that's not going to be responsible for the juddering; unless maybe it's contaminating the pads but I didn't see any evidence of that.

I did find that the bottom caliper slider was seized solid; eventually coming out after lots of penetrating oil and twisting with an adjustable spanner (initially with the help of a mallet!). The slider was cleaned up with paraffin, a wire brush and finally some wet and dry, while its bore in the caliper carrier were scrubbed out with paraffin and a phosphor bronze brush before being swabbed out with some kitchen paper. It all went back together with lashings of copper grease and the car tested - only to find it was exactly the same as before

Once I got back I dragged all the gear out again and checked the sliders on the passenger side; which were fine so I slung it all back together and called it a day.

So... my hope that the cause was something sticking somewhere appears to have been misplaced; the only thing I've not resolved is the probable sticky piston on the d/side, although I don't see how this would cause the symptoms I'm experiencing.

The passenger side disk has both far more runout (which should be accounted for by the sliders to a large extent) and thickness variation (which won't) - so I'm now back looking at this and considering my original idea that the disk might have slowly worn unevenly as the result of a warped hub flange. Sadly this isn't something I can easily check or remedy myself; and looks like whatever the remedy it's going to cost me for yet another set of disks

 

[Fastpedaller]

Have you checked other suspension parts that may give judder when the brakes are applied eg ball joints, track rods/track rod ends and tie rods that control the fore/aft movement?

 

[Fastpedaller]

Thanks - wheels and nuts are all original though as far as I'm aware. At some point I'll try to remove the caliper, soak the piston in penetrating oil and attempt to wind it in. If this cures the issue I'll pay a grown up to replace it; otherwise I'll keep on looking!

Have you checked the wheel nuts to ensure they don't bottom out on the hubs? It's strange that when new discs are put on it seems to cure it - that's exactly what happened with my mates' car! Could be the re-torquing of the wheels masks the problem, and once the wheels have 'flapped around again' it comes back? I realise I posted the previous note about checking suspension parts to ensure they are good - I can't see that being helpful as replacing the discs is unlikely to affect the outcome is it's a suspension part. Worth checking anyway I guess.

 

[wafter]

Thanks @Fastpedaller!

As you acknowledge I don't see how suspension components could be causing this - I guess slop in bushes / joints could exacerbate it, however as you say new disks should have no influence on these bits while the car's been through three MOTs with this problem and nothing's ever been picked up on. Unfortunately due to my lack of facilities I'm unable to investigate any of this myself

I'm pretty resolute that there's no issue with the nuts - they have a pretty beefy rad on their mating surface with the wheel, meaning that the rim would have to be paper thin in this area for the nuts to be bottoming out on the hubs.

I think really the next viable step would be to replace the passenger side hub and wheel bearing, along with yet another pair of disks. I'm on the fence about doing this as the car feels increasingly shafted and I don't know how much longer it'll last until becoming uneconomical to repair.

This is all so frustrating as I'd be happy to do the work myself if I had the facilities; while we all know that the bulk of most repair work on cars is labour so this could potentially save me a good chunk. I had hoped to buy something a bit more interesting / undulgent upon moving back to the city, however with the cost of borrowing going up this would be an all-in venture with zero funds left over at the end of the month, so is currently looking unlikely

 

[Fastpedaller]

Can I offer another suggestion........ I think someone else above suggested switching the hubs side- to- side to see if the problem moves, and that is good advice (I won't take credit for that one) , but you can do some basic suspension investigation by either using a helper, or possibly opening the window. drive or roll the car and press the brake and you may hear if there is suspension movement. Another one..... Jack the car up and put it on axle stands (usual safety applies of course). Get a long bar and put it between the wheel and ground and see if you can find any movement. I reckon it's a track rod end (or the steering rack/trackrods themselves), which won't show up in the test I've just suggested.
With one wheel on the ground, see if the raised wheel clonks if you move it swiftly side to side, only a few degrees.
I have 40 years experience of old cars, have built several kit cars and used to work in vehicle design...... we'll solve it!
Good luck.

 

[wafter]

Can I offer another suggestion........ I think someone else above suggested switching the hubs side- to- side to see if the problem moves, and that is good advice (I won't take credit for that one) , but you can do some basic suspension investigation by either using a helper, or possibly opening the window. drive or roll the car and press the brake and you may hear if there is suspension movement. Another one..... Jack the car up and put it on axle stands (usual safety applies of course). Get a long bar and put it between the wheel and ground and see if you can find any movement. I reckon it's a track rod end (or the steering rack/trackrods themselves), which won't show up in the test I've just suggested.
With one wheel on the ground, see if the raised wheel clonks if you move it swiftly side to side, only a few degrees.
I have 40 years experience of old cars, have built several kit cars and used to work in vehicle design...... we'll solve it!
Good luck.

Thanks - I can appreciate how a knackered track rod end might exacerbate the effect of a warped / variable-thickness disk, and that the sloppy joint might not be problematic with new, true, straight disks... however that still doesn't identify the root cause of the measured runout / thickness variation in the disks. I think this can only be down to a warped hub now.

Also, as above I only have very basic facilities (i.e jacking one corner of the car up on the supplied scissor jack as the car's a good distance from the house and I have nowhere proper to work) so unfortunately swapping disks and hubs about is a non-starter..

 

[Fastpedaller]

I don't think the runout is likely to be the issue. Track rod end is my top contender. I sympathise with the lack of facilities.
Good luck - and DO NOT get under the car when it's only on the scissor jack!

 

[wafter]

I don't think the runout is likely to be the issue. Track rod end is my top contender. I sympathise with the lack of facilities.
Good luck - and DO NOT get under the car when it's only on the scissor jack!

Thanks - I'm on the fence about runout as that could be accounted for by the sliding calipers, however 0.13mm of thickness variation surely has to have an effect.. I don't see how a sloppy track rod end on its own would cause vibration (surely under braking or acceleration it would just be pushed to one extreme of its play and remain there until the forces acting on it change).

Ta for your concern re. the scissor jack - IMO a lot less unsafe than doing the same with a hydraulic alternative, and fear not -I'm only working in the wheel wells so if the jack were to fail there would be clearance for my bits..

 

[Cletus Van Damme]

Maybe you should try asking the question on a Civic forum unless you haven't already. Somebody may have had the same issue as they're a very common car. I know from experience that the calipers are prone to seizing on some Honda's. Honest John forum is good for advice too.

 

[rogerzilla]

Discs must be fitted to a totally clean hub (use a wire brush to remove rust) and should be checked for runout with a dial test indicator. Lazy mechanics just slap them on and you get disc thickness variation a few thousand miles later.

 

[wafter]

Discs must be fitted to a totally clean hub (use a wire brush to remove rust) and should be checked for runout with a dial test indicator. Lazy mechanics just slap them on and you get disc thickness variation a few thousand miles later.

Thanks - I scrubbed the hubs when I fitted the disks but didn't check runout. I asked for this to be measured when the new disks were fitted the last time, and was told it was 0.1mm which was just within acceptable tolerance.

Really I think I've gone as far as I can with current facilties / without involving the garage..

 

[wafter]

Maybe you should try asking the question on a Civic forum unless you haven't already. Somebody may have had the same issue as they're a very common car. I know from experience that the calipers are prone to seizing on some Honda's. Honest John forum is good for advice too.

Thanks; tbh I've found a surprising lack of uk forums for the civic.. and figure causes are likely to be common regardless of vehicle (within reason!)

 

[CXRAndy]

Here are some figures regarding run out of hubs and discs
https://garagewire.co.uk/news/technical/recurring-brake-judder-solved-with-hub-run-out-measurement/

 

[PK99]

Thanks; tbh I've found a surprising lack of uk forums for the civic.. and figure causes are likely to be common regardless of vehicle (within reason!)

Hey presto

I've not read in detail, but a skim looks familiar...

https://www.civinfo.com/threads/juddering-brakes.340418/#post-4518322