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Truck shakes after brake repairs - brakes or suspension bushing?

I have a 1997 Ford F-250 Light Duty which is the oddball with the 7 lug wheels.

The brakes went out COMPLETELY a couple months back during a cold snap and a rear wheel cylinder was to blame. The fluid poured out as fast as I could put it in.

Anyway, due to time and weather constraints, I decided to take it to a shop. Since the truck essentially had two or three good brakings in it with a full fill of brake fluid, I went to the closest place to my house, only about 3 miles away. It needed new shoes, hardware, wheel cylinders, and drums on the rear.

I don’t think the shop did a very good job. For one, I don’t think they even drove the truck after the repair. The first time I hit the brakes there was a tremendous shaking from the truck. Then I began to smell the brakes smoking. I took it back a few days later and the parking brake cables were rusted so he replaced them. I don’t think he adjusted the one set of shoes back in as I was still smelling the brakes. I was able to work the drum off and adjust the brakes back in myself and there is no more smell.

The shaking is still there. Here are the symptoms.

  1. It shakes very little under light braking but gets worse as you press harder.
  2. You can feel pulsing in the pedal.
  3. Slowing down from 50-60 mph to about 20 is when you really feel it. You seen to hit the resonant frequency of the whole truck when slowing down to turn and the whole thing really shakes.
  4. I don’t think it is the front rotors but have purchased a set of rotors and pads that remain in the package for possible return. I don’t feel it in the steering wheel like where it tries to pull from side to side. The whole truck shakes so you do feel it in the wheel but I don’t think it is coming from the front brakes.
  5. I took the truck out and got it going pretty fast in reverse and hit the brakes a few times, mainly to make sure the rears were adjusted. THERE WAS NO SHAKING UNDER HEAVY BRAKING IN REVERSE.
  6. There was no shaking at all before the brakes failed on me a couple months back. It started immediately after the repairs. I can’t see another problem masking warped front rotors.
  7. “The seat of my pants” feeling is that it is coming from the left rear wheel.
  8. Frequency of shaking is correlated to wheel speed. Faster speeds = higher frequency of shaking.

Another buddy used to be really big into Mustangs. He says that maybe a bushing is bad/split. I am going to get under and look at this today as he said it should be clear to anyone if there is a problem. He says the bushing was bad but the weight of the truck never allowed it to slip out of place. Then when it was put on the lift at the shop, the bushing might have slipped out of place and the problem started.

Any other suggestions? I am going to get under and see if anything looks out of place where the suspension mounts to the frame around the axle and differential here in a bit but besides that, I am at a loss. I will plan to take it to another shop that I trust more now that the brakes are working if I can’t figure it out.

From this distance, it sounds like an out of round brake drum.

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The drums need to be removed and the brake work inspected. The shaking when the brakes were applied sounded like the shop failed to clean the cosmoline off the drums but you then you said there was no shaking when applying brakes going backwards and that reduces the likelihood of that being the cause somewhat. reversing the primary/secondary shoe locations is a possibility. Close inspection is needed ASAP.

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sounds like whatever guy at the shop worked on the truck isn’t very good working on drum brakes

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Check the lug nuts?

I have had the wheels off so the lug nuts are tight. I wonder if the shoes are reversed as mentioned. Would they go on backwards? I didn’t feel like messing with this so took it to a shop. Now I guess I will be messing with it some more.

If I took the drums off and took pictures, could you tell if the shoes are reversed? I had the drums off before and didn’t see anything loose but wouldn’t have realized if the shoes were in the wrong place. I will take pics and post them here if that helps, otherwise I am about ready to just take the thing to another shop I trust.

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Yes the shoe’s can be put on reversed I can’t remember of hand weather the short shoe goe’s on the front or rear bit it will make a difference.

It looks like the long shoe goes to the back. I will pull the drums and look.

I wondered about an out of round drum. These things are factory new and got replaced once as defects during this whole ordeal with the warranty. They came from OReilly if that matters. I figure they are all the same.

The shoes look like they were mounted fine on the left side. The slightly longer shoe with more material is on the rear (left of picture). I don’t see any strange wear patterns on the drum but there is a groove. I figure a small rock got in there. I use this thing on my farm and gravel roads.

A couple people have told me I should probably just go ahead and replace the front rotors to be sure. They say it might manifest differently if some problem with the braking system masked this before the repair. It just seems so odd that this happened right after the work. I never felt even a hint of this before.

I feel like I would just be throwing parts at an unknown problem by changing the rotors. I have done the pads in the past and they still have plenty of meat. On the other hand, I would save the cost of just taking it to the shop by going ahead with the replacement with the parts I already have on hand. They are new in the box so could be returned as well.

I am going to put the left side back together and get pics of the right side next. I can’t see anything out of place here but I am not a drum brake expert. That is why I took it to the shop!

I just took apart the other side and it looked the same. The shoes were in the proper location and nothing seemed loose or out of place. There were no odd wear patterns on the drum.

Considering all this and the fact the drums were both swapped under warranty when I told the store about the problem, I am starting to wonder if maybe the front rotors are the issue. The brake fluid was purged during the process and the brakes bled. The system leaked so much fluid it was probably entirely exchanged due to the leak and repair, especially considering that I refilled the system to drive it to the shop.

Could old fluid, air in the lines, or something else have masked a problem with the front brakes? My gut tells me it isn’t the fronts but again, I am not an expert and that is why I took it to the shop when the brakes failed in the first place!

Front rotors are a lot easier than working with drums and I have the parts. The weather is nice today and my business is considered essential so I will continue to be working so will have money but maybe not the time to deal with this. Some simple jobs like this take less time if I do them instead of driving to a shop, waiting, and paying them to do it.

I think I am going to just head out and eliminate another variable!

OK, I was about to change the front rotors when one of my buddies called. I had that side up on a stand and the wheel off. He had one more suggestion.

Find an empty road (not hard to do these days) and use the parking brake to stop. This would isolate the rear brakes and if there was no shaking, that would indicate the drums are fine. Well, I did this and there is still shaking but not nearly the amount as when the normal brakes are used. I did manage to lock up the rear wheels one time and overcame that by hitting the gas at the same time. I definitely think something isn’t right with the rear brakes but now I am realizing the shaking is worse when the normal brakes are used.

This either means that.

  1. I have problems with both front and rear brakes.
    OR
  2. The brake cylinders load the drum brakes up differently than the parking brake cables so the shaking is worse

Any insights into what I found with this test?

Can you measure run-out on the front rotors?

Do you have a dial indicator?

How about the rubber hose’s?

Just for grins and giggles bevel the ends of the brake shoe pads, use crocus cloth to buff up the pads and the drum machined surface… Whatta yah got to lose?

Maybe this is’t a bad idea. I seem to recall the leading and trailing edges of the shoes having a slight bevel. I can see it in the pictures I posted above.

Someone else I know also suggested just leaving all this alone for a while and just drive the truck to see if it smooths out a tad. I could tell I got the brakes pretty hot today with all my testing and they seemed to actually feel a little smoother afterwards. This is a farm truck that doesn’t get a lot of miles. Maybe I should just drive it a bit and see what happens before doing anything else. Maybe something needs to wear in.

The rubber lines look fine from the exterior. I assume you are talking about the last little lines to the calipers and cylinders. I have read that these can deteriorate from the inside, causing problems. Do my symptoms jive with this problem?

I know some of the hard metal lines to the rear needed to be replaced during this job.

I might get a dial indicator and measure the runout. Are the ones from Harbor Freight decent or junk?

https://www.harborfreight.com/search?q=dial%20indicator

If they are OEM they may be deteriorated enough so that the pressure is slow to release.

hi i went with the same problem found front rotors or rear drums out of round. good luck

I wonder if a bad lot of these drums was made. I mean I am on my second warranty set and this is what I got.

I don’t know the age of the rubber lines but remember that the shaking was still there when I used the cable operated parking brake to only activate the rear brakes. I am not saying the rubber lines are solid but I think there is another problem. Remember there wasn’t shaking until the work was done.

It usually has to do with how they were stored on the shelf, to many places store them on their edge which gives them a flat spot.

I’ve always had new drums turned just to make sure they are true and round before I installed them.