Need a little help diagnosing/solving this issue. I bought this 96 F-150, 4.9L/E4OD, 2WD a year ago with 93,000 miles. Since that time it always had a pulsing uneven braking pattern, at most any speed. I recently took it to a tire/brake shop to have the brakes checked / tires balanced (I have a minor shimmy between 45 and 50 MPH and didn't know if it was related to the brake issue). I had the front pads replaced, rotors turned, tires balanced. This didn't really solve my problem. So I did my first rear brake job, replacing shoes, hardware, and having the drums turned. They were a little warped and one of them gave some problems toward the outside, but 2 more shallow cuts fixed it.

I'm not quite sure how to properly adjust the new shoes. After my first test drive the hubs were pretty hot. I jacked it up and one was rubbing a good bit. I adjusted best I could, but when I rotate the wheeel, part of the turn it's not rubbing, and part of the turn it is. Is this correct? It seems like it should be rubbing all around or not at all if the drum is round. I also notice that the rotors are very hot up front (hotter than rear).

I still have the shimmy and a (greatly) reduced brake pulse. I noticed the forward shoes on the rear were more worn than the shoes closest to the rear of the truck - normal? The tires are not new but not totally worn out either. Maybe another 5 or 10K left in them. Should the front rotors be checked again. Front end components?

Thanks in advance for any suggestions.

Jim

 

Did you put the short shoe toward the front and the long shoe in the back on each side? Fords are also famous for the emergency brake cables freezing up with rust. This will cause a shoe heating problem. I adjust the shoes by turning the star wheel till I can't turn the drum at all. Then I back off till it turns with a little drag. Uneven contact is normal when you are adjusting. There was another guy awhile back that had a seemingly unsolvable brake shimmy and it did turn out to be a tire. Maybe you can rotate them and see what happens.

 

Did you install the shoe with least legnth material towards the front of the vehicle, on both sides ? The long legnth shoe faces the rear of the vehicle, on both sides . I pre adjust by open ing the screw until I can just get the drum on over the shoes with minumal effort. This should produce a slight rub over most of one full round of the drum. After the vehicle is back on the ground , I apply the park brake several times, then drive in reverse and firmly apply the brakes. This will finish adjusting the shoes. Concerning your pulsing problem, if the rotors are not warped again, check to make sure the caliper pins were installed correctly, narrow side vs. wide side---very easy to overlook. If that doesn't check out, I may blame a tire that has a broken belt or shifted belt giving way under braking pressures.
Phil

 

Hey- I dont know all that much about brakes, but nobody else seems to be responding to your post, so what the heck, i might as well. If the shimmy is happening all the time, you will want to look at things other than the brakes, the most obvious being a front end alignment. The second would be if the vehicle has even been wrecked. Any kind of frame damage can cause shaking at any speed, that can pretty much never be fixed without winning the lottery, or selling the truck to someone else! So, get under it. In trucks its pretty easy to see the frame even just through the wheel wells, look for anything that looks like a crease. If you have any doubts, and still care at that point, bring it to a mechanic, throw it on the lift, and look more closely, or even ask a body man. OR, check carfax.com with the vin. The wear issues seem normal to me on the brakes, but i really dont know that much, so i would wait for another more educated response before making any desisions. But, the front end alignment (which could be thrown out of whack by even just a good pothole), for under $100 could be key. Good Luck, mike

 

Thank you all for your posts. On the short shoe/long shoe issue (which I was unaware of), hopefully I have them correct. I have them installed where the lettering on the edge of the shoe is facing outside on both wheels. Is this a good enough indication or do I need to pull the drums again and measure?

I think I may need to tighten the adjustment. When I first test drove it, the brakes seemed to be working pretty good. Then when I found the drums to be rubbing fairly hard, I retracted the shoes like I said where it only rubs about 1/2 revolution. This results in almost no tension on the star adjuster, and made my brakes grab worse when driving. Maybe I should tighten them back up some more? As long as I can rotate them by hand, it doesn't seem like they would be too tight, because they should "wear-in" within a short time. Is this correct? The truck sure didn't seem to jump around as much when I had them tighter.

I am also looking into buying some new tires. On alignment, I was holding off because I may end up raising the front about 1.5 to 2 inches, and from what I understand, an alignment shop may have to use some shims to get the camber back normal. I was going to have it all done at one time.

Thanks again,

Jim

 

I know it is a pain, but I would pull the wheel off and make sure the shoes are on correctly. The difference is pretty dramatic so you can probably tell by looking at the shoes. As far as adjustment, if your close, like the other poster said, they will adjust themselves if everything is installed correctly by backing up and hitting the brakes a few times.

 

Thanks for helping a not so accomplished brake mechanic. You guys were dead on with the short/long (primary/secondary) shoe advice. I had to change the left rear setup. Once I did this the drum drags all the way around instead of catching 1/2 revolution. A moderate road test proved a dramatic improvement.

I still have the right side rubbing more on part of the revolution, although everything appears to be correct in there. This (or something else) is causing a minor break drag when pulling up to a stop, like you can feel it catching more during part of each revolution. I don't know if this is a tolerance problem and/or if it can be fixed. This is also the side that we had trouble turning the drum. The bit starting screeching in the last 3/4" toward the edge and we had to run it through 3 more times a few thousandths at a time. I would like to resolve it, but the truck is very much more drivable now.

I have sucessfully completed many projects over the years on various vehicles using a Haynes shop manual. I think they blew it on this one by not including information on the primary/secondary orientation.

Thanks again to everyone who posted. If you have any ideas why I'm still getting a (greatly) reduced pulse or drag, I would sure be interested to hear them.

Jim

 

Back to square 1. After driving my normal route to work, I realize the problem is no better than before I did anything. The truck is still jumping all around. I'm wondering if the drum is defective on the right side, not drilled correctly maybe. Maybe I should try the left hub on the right side to see if it has even pressure all around like it does when installed on the left side. If so, then maybe I need to buy a new drum. I don't know what else could be the problem. The short shoes face front on both sides, but the right side still does not have even contact, it only rubs about half the revolution when turned by hand. The left side seems the same all around (after reversing the shoes).

Thanks,

Jim

 

I had a similar problem on a ranger a few years ago, a real bad pulsing brake. It turned out that the right brake drum was out of round so bad that it could not be turned so I replaced both drums. While I was changing the drums I put in new shoes and while I was doing this I found that the slave cylinder on the right brake was only working on the front half and that the back half was so badly rusted I had to replace the slave cylinder(they are cheap anyway). Perhaps the problem of the out of round drum was caused by only the front shoe working. The old front shoe was worn way down and the back one was just as good as a new shoe. Perhaps you are experiencing the same problem. It is worth having a look at for all the time it takes. You can push on one side and the other sid eshould move in the opposit direction . Don't push so hard that the piston pops out though, also, slide the dust boot off and lokk to see if the cylinder boe is rusted as it may restrict the travel of the piston and cause uneven brake shoe pressure.
Good luck, SR

 

What exactly is the truck doing? Can you feel it in the steering wheel or the brake pedal or just in the truck itself. It's been my experience that the rear brakes usually contribute little as far as stopping the truck-especially unloaded. If the truck is hard to control and darting around under braking my vote is the tires.

 

you have done everything but replace your tires, try to rotate them and see if you see a difference. tire people will tell you that individual tire/rim combinations can be problematic to balance since you cannot put a load on the tire while you balance it. i have that on my mazda mpv, so every 7500 miles i have to deal with the shimmy. good luck and if you have any success post it for the rest of us.

 

Thanks for your posts. I will try to explain how the vehicle reacts while braking. Going say 45 mph, apply light to moderate brake as approaching a traffic light. The truck lurches rapidly sort of in a up/down pattern. Without changing brake pedal pressure, the truck is slowing and the rapid pulsation gives way to a more moderate and slower rythm. As you drop below 15 mph down to 0, it feels more like you are depressing and releasing the brake pedal more and more slowly until you stop, like something is dragging. I don't feel much in the steering wheel as far as I have noticed.

I may be wrong, but I feel like this is related to the way, when on jacks, the right drum is not in contact with the shoes for the complete revolution. Much like the left one was before I corrected the primary/secondary orientation. As I said before, the right drum also was problematic when being turned, but was eventually machined out OK. Would it hurt to tighten it up some more? I've tried reversing and braking to adjust, but when I jacked it back up, it still didn't have much contact during part of the revolution.

I haven't checked into the caliper issue but it looks like one way or another I'll have the drums off again and can check. Someone can stroke the brake while I verify that both shoes respond.

On the tire issue, I agree and am planning on getting new tires due to the minor shimmy I have at certain speeds, and I think new tires would improve the looks and ride of the truck.

Don't feel obligated to resolve this. I appreciate all the effort to this point. I may have to take it somewhere if I can find a really good shop. It's just that a lot of the time I like to do my own repairs so I'll know what's been done and hopefully done right.

Thanks,

Jim

 

This sounds exactly like what my Ranger was doing. Pull the suspect brake drum and check to see if the slave cylinder is indeed working from both sides. You can have someone lightly press on the brakes to see if both pistons come out. If they don't this is most likely your problem, Repair or replace the slave cylinder and recheck the drum for trueness. You may neesd to replace it as well. Metal has a memory and even though the drum was turned it may go out of round again when the brakes are applied. Also do a "ring" test on the drum, that is , support it through the center on a hammer handle and tap it with another one. The drum should have a bell like ring to it, if not there could be a crack in it somewhere that would show up when the brakes are applied Good luck.

 

I changed the right rear wheel cylinder last night, and did not notice a difference. If I change the left wheel cylinder, are there any more parts that could be causing this? Is there an anti-lock brake device on this vehicle that could be defective?

So Far:
Front Pads Replaced, Rotors turned
Front Seals, repack bearings
Tires Balanced
Rear Shoes Replaced, Drums turned, Hardware replaced
Right rear wheel cylinder replaced

 

No one has mentioned this yet so here is another posability. Every time the brakes are applied, the metal part of the shoe rubs on the backing plate. Over time the backing plate can become groved. Once this happens, the shoe will not be able to move smoothly as it will get stuck in the grove. I am affraid to say that to check this, you would have to pull the drums again, pull the pads, and then look at the backing plate. It is also not a bad idea to put a very small dab of brake lubricant on the contact points of the backing plate and on the anchor pins that the shoes rotate on. By the sounds of things, you soon will be recruited for a pit crew as you will have had so much practice taking wheels off!! ;-) .
On a brighter note, with a F150, you likely don't have the floating axle and thus do not have to pull the axle each time.

Good luck.
Bob