Brakes Drums catching/pulsing

ggradtech · Dec 18, 2019

I have brand new drums installed. I also had these new ones "turned" since they were a bit out of round. When I'm about to stop, I can feel the brakes catching or pulsing just a tiny bit. It's like they hit a high spot on the drum, let go, and do that again. I don't feel it, except when I'm almost at a full stop. The brakes don't catch at all or bind when I'm in neutral and slowly coasting. I had the mechanic service my e brake and he adjusted the rear drums as well. The e brake is perfect now (it was a mess before that), but this catching issue hasn't been resolved. It was doing it before the new drums and adjustments, and it's still doing this. Could the shoes be glazed over in a spot or two? Thanks.

Blown88GT · Dec 19, 2019

I did them myself a few years ago. There is no dedicated e-brake adjustment. They will self-adjust when moving backwards & then applying the brakes. You may have to do this 100 times before it adjusts properly.
Remove the drum & clean the drum & shoes with brake cleaner. Don't use it sparingly, about 1/2 can per side. Put a pan underneath to catch it all. Wipe down the shoes & drum with a clean rag before the brake cleaner dries.

Noobz347 · Dec 19, 2019

ggradtech said:
I have brand new drums installed. I also had these new ones "turned" since they were a bit out of round. When I'm about to stop, I can feel the brakes catching or pulsing just a tiny bit. It's like they hit a high spot on the drum, let go, and do that again. I don't feel it, except when I'm almost at a full stop. The brakes don't catch at all or bind when I'm in neutral and slowly coasting. I had the mechanic service my e brake and he adjusted the rear drums as well. The e brake is perfect now (it was a mess before that), but this catching issue hasn't been resolved. It was doing it before the new drums and adjustments, and it's still doing this. Could the shoes be glazed over in a spot or two? Thanks.

"Out of round" dictates a replacement. I can see new pair having an uneven surface and requiring a resurface but an out of round drum, is a no-go.

Blown88GT said:
There is no dedicated e-brake adjustment.

There is but perhaps not like you'd think:

The "Brake Adjuster" listed above can be lengthened and shortened by turning it. This device has "teeth" on it. When you are backing the car up and you hit the brake, the Brake Self Adjusting Kit arm, turns the Brake Adjuster. Of course, you can set and adjust this part manually during installation. You can also manipulate with a flat tip screwdriver through a slot in the Backing Plate Assy after installation.

Blown88GT · Dec 20, 2019

All drum brakes, rear or front, have that adjuster. It has nothing to do with the emergency brake.

Blown88GT · Dec 20, 2019

Deleted.
Server error caused double posting.

Neuron · Dec 21, 2019

I wouldn't let a car out of the shop until that was fixed. Take it back, and I agree on the new drum being out of round.

Noobz347 · Dec 21, 2019

Blown88GT said:
All drum brakes, rear or front, have that adjuster. It has nothing to do with the emergency brake.

Those adjusters have everything to do with the E-brake. The throw on the e-brake brake cable is fixed. Until the brake adjuster is properly set (manually or automatically) then the gap will be too large for the throw.

Blown88GT · Dec 22, 2019

Noobz347 said:
Those adjusters have everything to do with the E-brake. The throw on the e-brake brake cable is fixed. Until the brake adjuster is properly set (manually or automatically) then the gap will be too large for the throw.

Yes. The point I was attempting to make was that the adjuster is not exclusive to an e-brake. Most others have an e-brake adjustment on the e-brake cable.

Noobz347 · Dec 22, 2019

Blown88GT said:
Yes. The point I was attempting to make was that the adjuster is not exclusive to an e-brake. Most others have an e-brake adjustment on the e-brake cable.

Mine was that there's an adjustment but that it's a roundabout way to get it done.

That's what I meant when I said:

Noobz347 said:
There is but perhaps not like you'd think:

ggradtech · Dec 23, 2019

I didn't mean "out of round" per se. I meant that the new drums needed to be "turned" since they had uneven surfaces. I'm having the issue still. I'll get it back to the shop at some point. The issue only happens when you are about to fully stop. Just as you are about to fully stop, (Maybe the last 10 feet or so) I can feel the brakes surging. Almost like there is an uneven surface area on the drums.

Olivethefet · Dec 23, 2019

And your sure it's the rear breaks and not a front disk issue?

ggradtech · Dec 24, 2019

I'm not 100% sure. Usually, a front rotor.that is warped will be pretty obvious on the highway when you hit the brakes. I'm gonna check the fronts for even wear next. Thanks for reminding me.

jrichker · Dec 24, 2019

ggradtech said:
I have brand new drums installed. I also had these new ones "turned" since they were a bit out of round. When I'm about to stop, I can feel the brakes catching or pulsing just a tiny bit. It's like they hit a high spot on the drum, let go, and do that again. I don't feel it, except when I'm almost at a full stop. The brakes don't catch at all or bind when I'm in neutral and slowly coasting. I had the mechanic service my e brake and he adjusted the rear drums as well. The e brake is perfect now (it was a mess before that), but this catching issue hasn't been resolved. It was doing it before the new drums and adjustments, and it's still doing this. Could the shoes be glazed over in a spot or two? Thanks.

If you got the rear brake drums really hot when bedding in or adjusting the brakes and then parked the car with the emergency brake set, it may cause an out of round condition in cheap drums.

Drum brake assembly

I recommend that you print this post and tape the first drawing up in front of you when you reassemble the brakes. It is very easy to do it wrong and without the drawing in front of you.
The springs and shoes are position dependent, so look closely at the drawing when you put it back together. Make careful note of the FORWARD ARROW that points you towards the front of the car. When you install the brake shoes, remember: short shoe goes towards the front of the car.

Here's two pages out of the factory shop manual...

Rt jam · Dec 26, 2019

To verify front of rear. Run the rear on axle stands and note if the pulse is still there. Contrary to millions of theories. Pulsing is not an out of round condition. It is often a sticky spot in the braking surface. It's hard to imagine on drums but we have all seen a rotor with a slight rust build up after rain or a few days of not being driven. It has rust on all of it's surface except for what was behind the pads.

How about the axle. If it's bent it will run the drum off center too.

ggradtech · Dec 26, 2019

Axle seems fine. Before the drums were turned and the parking brake adjusted, it was really grabbing badly. I would come to a stop and it would actually cause the car to stop sooner due to just the grabbing effect. Now I have the parking brake just perfect. It will coast and move without hardly any incline/decline in the road surface when in neutral. It's just the very slight grabbing at this point when you are just about to fully stop.

General karthief · Dec 26, 2019

Ok, lets focus on a different part of the brake system, wheel cylinders?
this is going with the idea the springs and shoes are installed correctly.

ggradtech · Dec 26, 2019

Hmmmm. Good idea. Is it possible that 1 of them might be failing and causing uneven pressure to be exerted on only 1 side or perhaps on 1 side more than the other? Maybe I should just swap them for new ones? It's cheap anyways and they do look pretty old.

General karthief · Dec 26, 2019

You have addressed the common sense stuff back there, like I said, springs and shoes installed correctly, drums are true, axles are straight the next thing are the wheel cylinders.
this is all dependent upon the problem is in the rear.

ggradtech · Jan 2, 2020

I think I've corrected the issue. I checked the fronts and the passenger rotor seemed a bit uneven when I spun the rim while jacked. I swapped out the rotor, and it seems like it's now fixed. Fingers crossed that it is. Thanks guys.

90sickfox · Jan 2, 2020

For future reference. While driving gradually pull the e brake handle without hitting the brake pedal while going above 10mph ( keep the button on the handle pressed ). It you don't feel the pulsation in the handle or in you seat then it isn't the rear brakes. Just saw this post.

Brakes Drums catching/pulsing

ggradtech

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I will own your nuts! LOL

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Rt jam

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General karthief

wonder how much it would cost to ship you a pair

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General karthief

wonder how much it would cost to ship you a pair

ggradtech

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90sickfox

Wasn't a pretty sight...and I've got big hands

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Brakes Drums catching/pulsing

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I will own your nuts! LOL

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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Wasn't a pretty sight...and I've got big hands

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