Magnetic braking system

Submitted: Thursday, Dec 13, 2012 at 07:12
ThreadID: 128441 Views:2469 Replies:10 FollowUps:5
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Can anyone help us. The hubs on our BT 20 ft van are running hot. Bearings have been redone, so it's not the bearings. It's the brakes. Brake bands have been replaced and adjusted, but its only the x2 diagonal wheels that are giving us the problem. The other x2 wheels are as cool as cucumbers. This is causing us grief after only 20 klms. We think it could be something to do with the magnetic braking system. Any suggestions???
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Reply By: Deleted User - Thursday, Dec 13, 2012 at 13:10

Thursday, Dec 13, 2012 at 13:10
I would start by backing off the brake adjustment. Look in Hints and Tips on how to do it.
AnswerID: 585144

Reply By: sharon&ian - Thursday, Dec 13, 2012 at 17:11

Thursday, Dec 13, 2012 at 17:11
We've done all that Ern, thanks for the reply
AnswerID: 585145

Follow Up By: Noosa Fox - Thursday, Dec 13, 2012 at 20:15

Thursday, Dec 13, 2012 at 20:15
Have you jacked up the problem wheels and spun them to see if the brakes are rubbing?
Also while the wheel is off the ground, grab the wheel both in a horizontal plain and vertically and see if there is any bearing movement. Just because they say they have been done, they may not have been done properly.

Brian
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Reply By: Wherrol - Friday, Dec 14, 2012 at 04:18

Friday, Dec 14, 2012 at 04:18
Hi Sharon and Ian,

T'was wondering if the castle nut on the bearings was put on too tight.

Cheers

Sharon
AnswerID: 585146

Reply By: sharon&ian - Saturday, Dec 15, 2012 at 22:01

Saturday, Dec 15, 2012 at 22:01
Thanks for these replies, but we have these wheels off seems like a thousand times and have done all that is suggested here. Have spoken to electric brake people which seems to be a problem with the magnetics. Have bought new magnets which work the brake bands which will try before going to an autolekkie.
AnswerID: 585147

Follow Up By: Turist - Sunday, Dec 16, 2012 at 00:21

Sunday, Dec 16, 2012 at 00:21
Not sure what model/make your brakes are but;
Brakes have leading and trailing shoes.
With some models it is possible to assemble the shoes in reverse order and this can cause brake binding.
If new linings have been bonded on it is possible that the problem lies there.

The entire brake assembly including backing plate is "handed", they fit either left or right side of van.
You would not be the first to find that 2 of those are also on the incorrect side.
There should be a stamp in the back of the plate "LH" or "RH"
Something else to check.

Bob
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Reply By: Freewheelers - Sunday, Dec 16, 2012 at 03:22

Sunday, Dec 16, 2012 at 03:22
hi guys
we had a similar problem if you look at post 8395 on the owners forum it will explain our situation
if you want to discuss it send me a member message or give me a call
cheers
AnswerID: 585148

Reply By: Spannl - Saturday, Jan 05, 2013 at 03:52

Saturday, Jan 05, 2013 at 03:52
Hi Sharon & Ian
Have you sorted out your problem with the hub?
I have 1hub that is hotter than the rest as well. Done all the stuff you have done but still is hotter than the rest.
I think I have taken out a good set of bearings and replaced them for no reason.
Also surprised to find that BT are not using offroad brakes.


Cheers
AnswerID: 585149

Reply By: sharon&ian - Saturday, Jan 05, 2013 at 06:26

Saturday, Jan 05, 2013 at 06:26
Thanks for the reply.
We still have the standard brakes that come with BT, however the bands were replaced with the same bands, even though the previous bands were down to 50%. The same wheels were running hot with these bands. The heat of the wheels now is such that you cannot touch the hub.
. We have adjusted the right hand rear brakes right off to minimise the overheating problem we have on that wheel. Prior to doing this we had slight scuffing on that brake system, which appeared to be creating the overheating problem, even though the other brakes were adjusted the same.
We have also replaced the electromagnetic brake actuators on the brake system, which has eliminated the problem on the left hand front axle, but not the right hand rear axle. The same wheel seems to be scuffing a bit, maybe causing the overheating problem.
We have also backed off the manual handbrake system to ensure this is not causing the problem. We have been told by knowledgable folk that this can be a common problem, and they need a settling in time. We are heading to the isa tomorrow, so hopefully all has been fixed. We will soon see. Will keep you all posted.
AnswerID: 585150

Follow Up By: NIK `N` OFF - Saturday, Jan 05, 2013 at 07:45

Saturday, Jan 05, 2013 at 07:45
One thing that hasn't been asked .... when the bearings were repacked ..... are you confident that they were done correctly ie: grease packed into the bearing race properly, it could be a hot bearing .... which you will find out if it is as it wont last long ;-)

IMO no hub should be HOT to touch, warm is ok but you should be able to rest your hand against a hub.

By scuffing ... your referring to the tyres wearing on the edge? .... wheel alignment problem and i'd be surprised if that was causing the over heating hubs

Hand brake should be adjusted so when the handle is pulled it almost goes to the 2nd - 3rd last notch .....[ Simplicity advise to me ]
Cheers
Mick & Vickie

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Follow Up By: Noosa Fox - Sunday, Jan 06, 2013 at 03:50

Sunday, Jan 06, 2013 at 03:50
Mick,

Did Simplicity happen to say how to get the hand brake to hold the caravan stationary when the van is on a bit of a slope.
I haven't found anyone who can confidently say that the hand brake will stop a caravan rolling.
Spoke to another BT owner a few days ago who disconnected his as it simply would not work. Mine is also very poor.

Brian
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Follow Up By: NIK `N` OFF - Monday, Jan 07, 2013 at 05:52

Monday, Jan 07, 2013 at 05:52
I recall them saying the design of the hand braking system wasn't the best, the angles are wrong and the cable rubbing against the chassis. They changed the location of the handle by using the lower bolt hole and adjusting the cable as mentioned.

I don't have any major problems with the hand brake not holding but it hasn't been tested on a slope. When pulled it does lock the wheels so they cannot be turned when jacked off the ground.
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Mick & Vickie

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Reply By: sharon&ian - Saturday, Jan 05, 2013 at 08:50

Saturday, Jan 05, 2013 at 08:50
All we can say is that the bearings were packed with a bearing packer to the max.
By hot we ar referring to the drum wearing onto the band.
Wheel alignment has been done and would not cause it.
Hand brake has been done as you have just said..
Thanks so much for your reply.
AnswerID: 585151

Reply By: Spannl - Sunday, Jan 06, 2013 at 21:51

Sunday, Jan 06, 2013 at 21:51
Hi Sharon & Ian
Hope you have a good trip,to the Isa. Could be a little hot!
One thing I found on the wheel that is hotter than the rest is you seem to have to tighten the axle nut up more than the rest to take out the sideways movement in the bearings.
When you put the outer bearing on the axle it seems to have some play between the bearing and the axle as if the axle have been machined slightly under size.
The bearing I threw away thinking it was damaged because it had been spinning on the axle not because there was a mark on the axle but there was wear on the washer between the bearing and nut.
If the axle has been machined too small and you have to tighten the axle nut up tighter than the rest to take out the sideways movement this could be the reason.
What do others think?

Laurie
AnswerID: 585152

Reply By: sharon&ian - Tuesday, Jan 08, 2013 at 21:18

Tuesday, Jan 08, 2013 at 21:18
Just on the outskirts of the Isa with no overheating hub problems.
The affected wheels remain a tad warm, seem to have settled in with the distance covered. Thank-you everyone for your suggestions. We think that the shaping of the new brake-bands wearing into shape and the replacement of the magnetic actuators was the solution to our problems.
AnswerID: 585153

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