hubs running hot after being 'fixed' what else to look at ?

denmonkey · Senior Member

hubs running hot after being 'fixed' what else to look at ?

Kebbin · Guru

Sounds like the wheel bearing has been over tightened.

Joda · Senior Member

Bent axle? Distorted rim or brake drum, brakes adusted too tight, hand brake not releasing that side, stray 12v feed causing magnet to drag, distorted tyre or out of round, wheel alignment(toe in/toe out) usually found brake shoes not backed off enought, being a self servo drum brake they can tolerate a bit of clearance, are brake shoes centered on backing plate, guy to ask is aus-kiwi, He sounds like a competent spanner man. Good luck, Joda.

denmonkey · Senior Member

I'm leaning towards the electrics at this point.

It will go back to the shop tomorrow for them to check the mechanical side of things and if they report all is fine, I'll get under the check the wiring.
I know the earth on the 12v leaves a bit to be desired (read jayco standard) but I would expect it to impact both wheels.
That said, the passenger side, which is the one affected, is furthest from where the trailer feed comes in and the chassis earth point. This also puts it furtherst away from the aux battery, so less likely to be effected by that.
I've also read that there can be benefits to taking the earth/ground direct from the tug, so I may try this.
I had planned to run new trailer wire through from the plug. I guess this may move it up the priority list a little.

I've backed off the shoes on that side with no change and checked the hand brake. The hand brake doesn't even work when it's applied :) so it was unlikely to be that.

I can't advise if they machined the drums when the work was done, so will check on that.

Is it reasonable for me to ask them to take it for a run and ensure the hub isn't heating up before they call it good and I collect it? I don't want to wait till my next trip away to find no improvement.

cheers BRett

Joda · Senior Member

Nothing wrong asking for a test run, how else can you tell if its been fixed, make sure there is a bit of play at the wheel rim after bearing adustment (half a mil) and not over filled with grease, lets know the outcome, this sort of problem seems to crop up regularly, Joda.

wasn_me · Guru

Check the leading edge of the leading shoe has a good taper on it. If not it can cause the shoes to drag, (causing heat), also engage harshly.

patrol03 · Senior Member

It seems to me that there are several possibilities. Firstly there has been a history of poor quality magnets. Secondly there is an obvious bearing problem perhaps from poor fitting Thirdly,new backing plates must be correctly centered. The method used to do this is to loosen the four bolts securing the backing plate, adjust the brakes so they are extremely tight and well seated in the drum. At this point you tighten up the four backing plate bolts.Finally release the brake shoe adjustment and re adjust. Wheel bearing adjustment is best done with the wheel attached to the drum. I know it is a pain particularly if you have caps that are fitted from the inside the wheel. When adjusting your brakes, adjust them up tight then back off until there is just a slight swish when you spin the wheel. New linings, even when radiased prior to fitting do need a bedding in time before good braking is maximised. The only other possibility that could arise is that you have an off side unit fitted to the nearside or the leading and trailing shoes are fitted incorrectly.
Some of these items should give you some food for thought. Hope it helps.

hako · Guru

I'd be checking that the stub axle end - where the outer bearing sits - check it is not out of centre - this can cause the tapered bearings to not run in their cups correctly. This can be caused hitting a kerb. Also check the inner and out bearing cups are also true.

Good Luck

Peter_n_Margaret · Guru

Find a new mechanic that knows what he is doing.

Cheers,
Peter

Treecrest · Veteran Member

Would be worth checking Guru's suggestion.

I'd be checking that the back mounting plate is square to the axle - if not it could cause the brakes to not be center.

Shrek · Veteran Member

Brother in law had a similar problen with his new van with the lhs back wheel locking up when brakes were applied. A lot of time was spent troubleshooting the problem.

The issue was finally identified as the wrong backing plate fitted to this wheel. Alko brakes have a left hand and a right hand plate (rhs plate was fittied to the left hand side). Correct plate was fitted and no problem with brakes since.

Shrek

erad · Guru

Does your van had a breakaway braking system? If it does, it is possible that a crook earth on one side would make the braking system think it had no power at all, and apply the brakes (on that side only). Also, when you say it was really hot, where did you sense the heat form? Was it the wheel bearing itself, or was it the brake drum? If you can distinguish between the two, you have a better chance of diagnosing the problem.

oldbloke · Guru

wasn_me wrote:
Check the leading edge of the leading shoe has a good taper on it. If not it can cause the shoes to drag, (causing heat), also engage harshly.

A sounds likely to me.

Brenda and Alan · Guru

I agree with Peter & Margaret, go find a new mechanic.

Assuming that the overheating occurs whilst towing without brake usage

(1)Backing plates have no bearing on centreing brake shoes. They are not positioned in the drum by anything on the backing plate when the brakes are applied, they are self centreing. The supporting pin at the top stops the shoe set from rotating with the drum but is not positioning the shoes.

(2) The only difference I have noted between LH and RH on some backing plates is the position of the slot to adjust the brakes.

(3) Bent drums, bent wheels and wonky tyres won't cause a drum to over heat when the brakes aren't applied.

The two most obvious faults. Wheel bearings adjustment incorrect, or brakes adjusted to tight. You have said that backing of adjustment did not help. So I'd look at bearing adjustment first. Particular attention should be paid to the condition of the hub as it could have been badly damaged by the first bearing failure.

BUT this assumes that the work done was at least reasonably competent with the correct parts being used.

Alan

-- Edited by Brenda and Alan on Tuesday 20th of March 2018 08:07:22 AM

-- Edited by Brenda and Alan on Tuesday 20th of March 2018 08:09:05 AM

erad · Guru

Another possible cause is over-packing the bearings with grease. This will make the hub run warm or hot, but not necessarily the brake drums. This is why I asked earlier where the heat was coming from.

Possum3 · Guru

My ALKO ESC intermittently applies brakes when cornering - unit sent to ALKO (allegedly) by dealer who say nothing wrong. If your unit has stability control - disconnect and trial run.

denmonkey · Senior Member

Wow, thanks for all the replies.
I've just dropped it off today for them to check it out and will report back their findings.

The bearing were done as part of a rego check. On taking it out for its first run after that the heating issue on that side became apparent.
Upon returning it to them, they advised of an issue with the backing plate and suggested this was the cause for the overheating.
These were both replaced but the issue with overheating has persisted on the same side.

This suggests the bearings are still to blame I would think, but surely they would have been double checked when it went back to have the backing plates done.
They did say they repacked them because of the heat exposure.

I can see from above there are many and varied possibilities.
For now I'm working on the assumption the guys knowing what they're doing and the work they've done up to this point has been good.

Thanks for the input, fingers crossed.

Triggy · Veteran Member

denmonkey wrote:

Braking varies greatly from like they're being jammed on hard and skidding on that side to working normally.
When that side brake does grab, it is doing so hard, it pulled the nose of the car off to the right.

Any advice is appreciated.

cheers Brett

Your above post would suggest
A good indication that the brake shoes are not adjusted up enough. When the shoes move out to the drum it grabs at the top and jams
the shoes should only have to move slightly to make even contact with the drum . Or your electric brake controller is set to severe when the brake is applied causing jamming of shoes .
Gary
retired automotive teck

-- Edited by denmonkey on Monday 19th of March 2018 11:13:35 AM

-- Edited by denmonkey on Monday 19th of March 2018 11:29:32 AM

swamp · Senior Member

Hi
Drum out of round distorted
bearings in drum incorrectly seated
linnings not the same size as drum =radius grind
spindle bent
Wheel alignment and tyre pressures
any people donot adjust linnings correct Automotive tight ==slight noticable drag

Zero wheel brg play

correct voltage and earth to wheel ,mostly soldered

-- Edited by swamp on Tuesday 20th of March 2018 07:14:12 PM

KevinC · Senior Member

Could be that the left side is working normally and the problem is that the right side isn't working at all, or worse, has an intermittent fault which means it only works sometimes. That will cause the difference in temperature you found. Make sure the right side earth and magnet are checked.

Brenda and Alan · Guru

I think the poster is saying the hub is running hot as opposed to the brakes are running hot. To me that means that just towing the van without brake use the hub is heating up. If this is the case then, either wheel bearing or brake adjustment are the only possible causes.

Alan

erad · Guru

Most of the above responses talk about the brakes being the cause of the heating. Unless you are going down a mountain, the brakes rarely operate - bringing the rig to a halt shouldn't cause very much heating at all. To me, it sounds like the brake shoes may be dragging when they should be clear of the drums, or the bearing itself is getting hot (in which case it is probably the bearings too tight, or overpacked with grease). Wheel alignment won't cause the bearings to overheat - the tyres will get hot first. Out-of-round brake drums will only cause uneven drag when braking. They will not be noticed at other times.

For what it is worth, my single axle Jayco Poptop van has a problem with the left wheel. The tyre pressure monitoring system indicates that the pressures increase by up to 10 psi, regardless of the initial (cold) pressures, whereas the Right side wheel only increase by about 6 psi. I have tested with cold pressures ranging from 36 psi to 50 psi, and the left wheel still increases by around 10 psi as the tyre warms up. I attribute the difference to alignment - the axle has about 5 mm toe-in, which is far better than the original axle which had nearly 10 mm toe-out as originally supplied with the van. The tyres don't seem to be wearing as badly as they were before - they are wearing evenly at least this time, but to me the jury is still out whether Al-Ko has solved my problem. I cannot feel the hub as I drive along because of the Jayco hubcaps, but the brake drum doesn't get overly hot.

Moonraker · Senior Member

Denmonkey,
As you can see from the replies there is a number of reasons your brakes are faulty. Nobody can say what the problem is without a good inspection and test of you van and tug. The only way to get this sorted if you cant do it yourself and the mob you have tried again fail to find and rectify is to take the rig to a professional caravan service person/centre who have experience. So I suggest you investigate in your area for a reputable van service centre or individual experienced professional. You can then continue to use the same place for future services knowing its getting done properly.
Good luck.

diggerop · Senior Member

Probably not your issue but I had one that was running hotter than the others and after much head scratching and adjustments found out that the others wern't working properly and the hotter one was doing most of the work. Just as KC wrote about.

denmonkey · Senior Member

Just to report back, Kevin and Digger both nailed it.

Well Kind of, at least the final stage.

it went through a few stages to get where I am now.
Swapping the backing plates got me down from 22+L/100 to 16+ . So that was a good improvement but still not as good as it should be with the hub still over heating.

They finally decided the drivers side drum was not right and replaced that (no cost) as they said the passenger side was doing all the work and the drivers side not working at all.

To be honest I was not convinced of this theory but I ducked away for an over nighter and covered over 140kms a good portion on the freeway over 100km/h just to test and can report I even saw 13.7L/100 pop up on the dash for a little while.
Regular stops to check the temp.
The passenger side still got warmer than the drivers but nothing worthy of note. I can certainly hold my hand on it without issue.

Now they also re positioned the shocks from where they had placed them after the lift and I reckon that may also have had some impact on the whole deal.

The whole thing tows like a dream now. Very happy.

I'm happy with the way the guys responded when I took it back each time but obviously not happy it took 4 visits to get it right.
I'll probably not be going back to them for future work

thanks to everyone for their input