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Author Topic: Trailer brake shuddering  (Read 108 times)

Sylvain

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Trailer brake shuddering
« on: October 12, 2019, 10:10:35 PM »
Hello again everyone,
During our last trip with our LL I noticed some suddering/shaking while breaking withe trailer attached to the TV.  When the trailer is not attached to the TV everything is fine, no shaking.  I wonder what could cause that shaking?  I serviced the brakes and bearings before leaving for our trip.  Everything looked fine.  The brakes needed a good cleaning but the pads were good.  Does anyone experienced something similar?

Thanks

franks97

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Re: Trailer brake shuddering
« Reply #1 on: October 12, 2019, 11:10:49 PM »
If you have an adjustable trailer brake control in the TV try turning it down a bit.

Sylvain

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Re: Trailer brake shuddering
« Reply #2 on: October 13, 2019, 10:10:38 PM »
You may be right franks97, the higher the gain on the brake controller the more it shakes.

charliem

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Re: Trailer brake shuddering
« Reply #3 on: October 14, 2019, 10:35:43 AM »
The brake controller should be set so the trailer brakes help slow the rig, not stop the rig. They should just overcome the additional weight of the TT. Instructions included with some controllers suggest starting at the point where engaging the trailer brakes manually will lock them up, then backing off just a bit. This leads to way too much trailer braking. Starting with a low setting, drive a bit and stop several times normally such as at a stop sign. With no trailer braking you will notice longer stopping distance and the trailer will feel like it's "pushing" the TV. Increase the braking until the trailer just begins to pull on the TV. You don't want the TT brakes to lock up, especially on wet or icy roads. If you have a Tekonsha or similar the boost function can be used to temporarily increase the initial attack level if you need it under some conditions. It takes a bit of trial and error but when it's right it's beautiful  :) .
Any 20 minute job can be stretched to a week with proper planning

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DavidM

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Re: Trailer brake shuddering
« Reply #4 on: October 14, 2019, 10:59:48 AM »
Well I disagree a little bit with Charlie's procedure above and also have a potential solution for your brake shudder. The following applies to proportional brake controllers:

I do believe in the method of adjusting the brake gain until the trailer's brakes begin to lock up and then backing off a bit. I usually do this on loose gravel so it will be less likely to lock up on wet roads.

It is a compromise but I believe it gives you the best overall braking force. If you just adjust your brakes until you feel you are getting a little pull from your trailer you aren't getting much braking force.

Back to the shudder. LL's have drum brakes and when they get very hot (more about this below) they can warp and that causes the shudder. You can have them turned in a lathe if it isn't too bad and true them up. It can be a DIY job. Pull the wheel off and then unscrew the axle nut and pull off the wheel drum. Used to be that all auto parts shops would turn drums for you, but now you have to look for one. Should cost maybe $10 per drum to get it turned. Or you can take it to an RV repair shop and have them do it all.

How did they get so hot?. Well maybe because the controls were adjusted to give too much braking force or maybe the brakes were dragging all of the time due to the internal wear adjustment getting out of whack. Once the drums are trued up, reassemble them and see if they spin easily after hitting the brakes a few times to take up the slack from the drum turning . If not back off on the brake pad adjustment.

David

Sylvain

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Re: Trailer brake shuddering
« Reply #5 on: October 15, 2019, 01:44:28 PM »
Ok thanks a lot Charlie and David, it helps a lot.  I was also thinking that the drums might be warped.  The sad thing about having them turned is that I will have to remove the bearings and clean all the grease inside.  Anyway, I may end up doing just that!

Merlin

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Re: Trailer brake shuddering
« Reply #6 on: October 15, 2019, 07:53:26 PM »
Sylvain, Since you mentioned the brakes needing a good cleaning, I suggest doing that first. Just pull the drums off and vacuum the shoes (with a shop vac) and use brake cleaner (with protective gear) on all the metal, especially the drums. It will be a filthy mess but it may fix the problem and even if you end up having to lathe the drums everything will need to be cleaned anyway. I had a Nissan Pathfinder several vehicles ago (here’s lookin’ at you David) with rear drum brakes. When they were dirty with too much brake dust they would get very “grabby” when they were the slightest bit wet. That led to shaking and shuddering even with morning dew condensation. And while you have the drums off, simply look at them to see if there are any rusted/pitted spots or spots where brake shoe material has stuck from overheating on the inside friction surface. It should be evenly polished and smooth.
Michigan

Sylvain

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Re: Trailer brake shuddering
« Reply #7 on: October 15, 2019, 09:11:08 PM »
Thanks Merlin,
I did clean the brakes this summer before heading out for our vacation. There was a LOT of dust in there! I removed all the dust using my air compressor but I didn't clean the drums with brake cleaner though.  I'll do that next summer before the 2020 vacation, it may solve my problem!