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Jmkvalsund

Vibrations in rear drum breaks

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Long intro but please rear, this is driving me nuts: I bought new drums and shoes for the rear brakes on my Connect T230, 2011. Did however not manage to remove the old drums, using all the tricks in the book. Put the car in a workshop along with the parts. They magicaly managed to remove the old drums, put things together and returned the car. However there was now some rather heavy vibrations when braking, and since pulling the handbrake while driving  gave the same vibrations, this had to come from the rear brakes. Back to the workshop complaining, they didnt find anything wrong so they concluded  it had to an unbalance in the drums I had brought..I got hold of new drums, replaced them myself this time, still the same vibrations. I even replaced the brake cylinders on both sides to be sure they didn't cause any uneven pressure on the shoes. But still vibrations...

So, can the workshop have broken something in the suspension when using magical tricks to remove the original drums (unimaginary amounts of force..), or what can it be that I'm missing? The vibrations are harder the more force I apply on the brakes. When jacked up, the wheels are rolling without any spesific noise, and I cant feel any specific wear on either of the wheel hubs... Anyone who has any idea what can cause these vibrations?

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Check for play in rear wheel bearings.

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Did you check to see how the new shoes fit in the drum, is the shoe contact complete ? What does the contact pattern of the new shoes look like?

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On ‎6‎/‎22‎/‎2019 at 7:29 PM, mrtn said:

Check for play in rear wheel bearings.

I can't feel any play in the bearings, not when "twisting" the wheels when jacked up at least. And as far as I can hear, there is no noise from the wheel bearings when driving.

 

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19 hours ago, G B L said:

Did you check to see how the new shoes fit in the drum, is the shoe contact complete ? What does the contact pattern of the new shoes look like?

 

I'm afraid I did not. Would think the workshop that mounted the parts in the first round would have done that, at last when I came back complaining.

When I rotate the wheel, I can feel a kind of "unbalance", the shoes touches now and then on the left side. But I thought that would pass after a short period. Can this be the problem? Haven't been working with drum brakes for ages, but do remember them as quite easy things to work with...

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2 hours ago, Jmkvalsund said:

Haven't been working with drum brakes for ages, but do remember them as quite easy things to work with...

 

When installing new shoes into new drums, it's a good bet that the shoes do not exactly fit the curvature of the drum.  It used to be that shops which worked on drum brakes had the special tools to grind away a bit of the lining on the brake shoes so they they perfectly matched up with the curvature of the drum.  Now days,  with so few vehicles still using  drum brakes, finding a shop which still has the tools to do a proper job might be quite difficult.  That is, unless you took it to a shop which specializes in quality brake work.  Your 'average mechanic' probably doesn't have the tools to do it right  -  If he did, he would have fixed it properly when you returned it, assuming he knew much about drum brakes

 

Don

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13 hours ago, Beta Don said:

 

When installing new shoes into new drums, it's a good bet that the shoes do not exactly fit the curvature of the drum.  It used to be that shops which worked on drum brakes had the special tools to grind away a bit of the lining on the brake shoes so they they perfectly matched up with the curvature of the drum.  Now days,  with so few vehicles still using  drum brakes, finding a shop which still has the tools to do a proper job might be quite difficult.  That is, unless you took it to a shop which specializes in quality brake work.  Your 'average mechanic' probably doesn't have the tools to do it right  -  If he did, he would have fixed it properly when you returned it, assuming he knew much about drum brakes

 

Don

Thanks, then I know what's the problem. Question then is, will this stop when the wear of the shoes makes it fit the drum? Or is that so much wear neeeded that the wheel bearings will be broken first?? I'm not sure if there are any good brake workshops left around here...

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*Usually* all that's needed is the removal of a small amount of material at the very leading and trailing edges of the brake shoe and this *should happen* pretty quickly just by driving it  -  Don't try using a bit of the handbrake to hasten the process or you risk overheating things and possibly warping your new drums.  I would guess inside of a few hundred miles it will be gone and you will probably notice it getting better before that.  I really doubt you're going to damage the wheel bearings

 

Don

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The real reason it is hard to fine a shop with an Brake shoe arc grinder  is the dust problem .  There should be no asbestos in the linings, but you can't be sure. You can speed up the process by adjusting the brakes a bit tighter.  If you reverse the car smartly and stop it you will adjust the brakes . The brakes will feel, warm to the touch when they are adjusted properly . 70 or 80 degrees c.

 

 

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