What have I bent? (front offside wheel hot)

[CMF_queazocotal]

Ok...
Sorry for the slightly protracted story.

~8 weeks ago, I was badly distracted in the car (passenger) and managed to mount a 30 degree earth bank alongside the road, at around 30mph, ending up with the car at a maximum of maybe 20 degrees tilt, before going back flat.
There was no apparent damage, and it carried on driving the same.

Now, while I was cleaning/painting the member under the bumper, with a trolley jack under it, this slightly bent upwards - maybe a total of 5mm, and was then bent back.

I happened to run the car without all of the undertray - urgent trip, and smelt a very hot smell.
I later found out that the left front wheel was hot after a short trip ~35C in the middle.

I assumed this was a brake caliper sticking.
However.
On removing the wheel, the disk will turn with difficulty - maybe 50Nm?
I then noticed that there was no apparent clearance between the front of the caliper and the disk. Never mind the pad.
I assume this means I've bent something, and it's this rubbing which is causeing the heat.

Is there an adjustment to let me move it slightly outwards? I don't see one.

No piccys as yet - having problems downloading from the camera.

It's quite possible that I've not noticed the warming of the wheel before, since mounting the kerb, as the car is not garaged, is in an exposed location, and it's the passenger side wheel.
Any thoughts welcome.

 

[CMF_kneival]

Do you have standard discs, pads and calipers? The running clearances are normally very tight on these things.

If you take the wheel off and put the nuts back on so they clamp the disc then what happens? Can you turn the disc?

The center of my alloys get hot if I have been doing some heavy breaking, the calipers and discs are steaming hot and transfer some heat to the wheel center.

Are there any clunks coming from your wheel when you are driving and turning, thinking maybe damaged CV joint? Is the CV cover ok?

Other then that im not sure, the brakes basically bolt to the wheel, so if something is bent its going to be something very serious like the hubs bent.

HTH!

 

[CMF_queazocotal]

I believe they are completely standard - car was bought in ~2000, second hand, and I think it's stock. There are certainly nissan part numbers on the calipers, though I haven't checked if it's the matching number.

I'm pretty sure it's actually in contact, not just close, there is no visible gap under bright light.

I haven't tried putting the nuts back on without the wheel - however, I felt it rubbing while I was pushing the car, so that's unlikely to fix it.

The disk can be turned, with difficulty.

There are no clunks or odd noises, and the car drove perfectly normally immediately afterwards, so I diddn't do more than get out, inspect the tyre, and check the pressure at a garage 2 miles away. Nothing obvious in the ~ 100 miles since either.

Only one alloy gets hot, so I'm pretty sure it's not normal.
I've been under the car - for other reasons - mainly keeping on top of rust, and not noticed anything glaringly obvious.

I'll get a better look tomorrow, when I have it up on axle stands, not the stock jack, and feel comfortable putting my head in the wheel well.

You say ... "the hubs bent".
Surely that'd cause a very obvious vibration/rubbing noise?

I haven't got my head round (either in the literal, or figurative) sense of how everything attaches in that ares.

 

[CMF_kneival]

Hmm perhaps its possible you could have damaged the bearing inside the hub which is causing the wheel and therefore disc to run at an angle to the caliper?

Deffo get the nuts onto the disc without the wheel and have a feel.

Normally when bearings are damaged you can rock the wheel with the weight off. It shouldnt move with good bearings.

 

[CMF_queazocotal]

Hmm. Thinking about it.
It seems to me (I have not been at the car since the last post) that somehow, I've either bent the wheel bearing housing/caliper mount, or somehow the caliper.

The disk can't be bent, or skewed on the bearing, as there is no vibration at all, and the disk turns smoothly - though with difficulty, throughout a revolution.
Anyway.
Tomorrow, I think I've got to take off the other wheel, and do some accurate measuring.
Probably the steering geometry too.

I don't think it's as simple as a damaged bearing, with excessive play unfortunately - as the force from the caliper should, without the wheel push it so that the drag is less than with the wheel on.

Anyway - at least this lets me fit my wheel rotation sensors, for tyre deflation detection, and remove all the plastic, so I can brush/paint any exposed rust.

 

[CMF_queazocotal]

Downloaded camera.
I believe the part number is 87321705/2.

And I see what you mean about the bolts, will try that too.

 

[CMF_Yom]

When you jack the car, be very very careful! (no its not wabbit huntin' season)

The lower radiator support on the k11 IS NOT LOAD SUPPORTING!

Only one point on the crossmember is designed for use with a trolley jack. It is a sort of flat protrusion with a hole in it. You'll know it when you see it.

 

[CMF_queazocotal]

That's what I used.
It buckled.
The front member is quite rusty, most of the bumper attachment fittings on the bottom pulled out when 'open'.
ATM, I'm looking for a K11 in a scrapyard.
I can take out the entire front member, up to and including where it joins the main structure in about 10 mins with a hacksaw, trim off the extra structure then weld it on easily.
Assuming I could find it...

It's possible it had been weakened by an impact - there is a dimple in the jacking point, where I think it's hit a post in the past.

 

[CMF_kneival]

Not sure if its my eyes playing tricks on me but your caliper looks to be drunk on the rods. Almost looks like it dips down towards the front?

Try removing the caliper and inspecting the rods, are they bent at all?

 

[CMF_queazocotal]

I tried removing both obvious bolts, then removing the caliper - it diddn't want to know. I'll have another look today.

 

[CMF_queazocotal]

Whee - thanks to the helpful suggestions, the problem is now 'just' a sticking caliper, without any suggestion of permenantly bent stuff.
Putting the nuts back on the disk, without the wheel did indeed give ~1.5mm of clearance on the front of the disks.
Now, to dissasemble the caliper.
I'll be taking pictures throughout the process, for edification of others.
One more point.

I hate 12 point sockets.
I'd forgotten how much.
Spawn of the devil.

 

[CMF_kneival]

Good to hear you found the fault.

You can strip down the calipers and remove the piston and clean it with brake fluid ONLY. This is not really advised without replacing the seals but I have done it on my two sets of calipers.

When you reassemble (before connecting to brake lines) make sure the piston is all the way in so there is as little air as possible.

Also when inserting the piston into the caliper be very very carefull as it can squirt fluid out of the hole (as I found out as it got into my eyes).

There is a good guide in the haynes manual on dismantling the brake system :-]

HTH!

 

[CMF_queazocotal]

Ok. After removing the back caliper mounting bolts, and hammering on the caliper with a big hammer (though swung gently) to persuade it to release its death grip, I now have it in my hands. (well, propped on the disk).
Sigh. Have no brake fluid to clean it - so will drain 10ml from the resovoir to do that with.
On the plus side, the pads are still quite thick, so it may only have been doing it for a couple of days - it has recently been parked up for a couple of weeks, doing the underside.

There is a guide in the haynes manual - but it kind of assumes that it's not stuck to the point you need to hammer it, to get the caliper to release from the disks, and I was reluctant, before seeing exactly how it all went together.

 

[CMF_queazocotal]

There is a horrendus buildup of crap between the spring clips, and the brake disks, which has stopped them moving easily - it was a struggle to remove them.
The guide pins seem in good condition.
The piston seems completely siezed - it's currently in the oven at 100C, and I'm going to fill the center well (carefully) when it comes out with cold water, to attempt to free it.
Been taking lots of pictures, so I can add them to "how to take off your caliper" for the unconfident.

 

[CMF_kneival]

I normally found the best way to remove the piston was to wind a bolt into where the hydraulic line went, this pushes the piston out. Or you can do it with a brass drift and hammer.

 

[CMF_queazocotal]

I did the bolt thing - till I ran out of bolt.
Then I did the drift thing with 2lb hammer.
It's all in bits at the moment. Tomorrow, I remove some rust on the outer face, so the seal can seat properly, put it back together, and go and get a new set of seals, and some fresh brake fluid.
I wonder if it's worth doing the other side at the same time.
What grease should I be using on the guide pins?
Thanks again for all the help!

 

[CMF_Yom]

The road salt really causes problems for you lot! I feel sorry for you!

 

[CMF_kneival]

Use some silicone grease or something, highish temp would be nice (not that they get mega hot but its better than having it melt).

 

[CMF_queazocotal]

Rust is NOT FUN.
I've gotten into the habit of not using spanners on stuff I need to remove without burring, but using an adjustable wrench.
put on nut, close as far as it'll go, wiggle a little, repeat, remove from nut, adjust a hair tighter, push onto nut with a slight wiggling motion to take the last layer of rust off.
Ideally this then ends up with the wrench so tight that it won't fall off if removed.
I found rust inside the brake bleed screw hole, all the way to the bottom :<
Everything that gets taken off gets wirebrushed to bare metal, painted.
Anyway, got nice 'exploded diagram' pics of caliper, for a how-to, and I haven't even broken anything dissasembling.

 

[CMF_queazocotal]

Back on now, just finishing painting under the various trim round that wheel, after removing rust.
Looks to be not too bad.

Caliper opens and closes well, and wheel moves easily after hard braking.

All I need to do now is to fix the damage the tyre monkey did to the jacking point next to it and put the trim on.