DFFECHSWU

Hello. I'm a sometimes poster on this forum and am looking for advice. I own a '93 F150 XLT Supercab 4.9L 4X4. I don't drive it much so that's why there's a gap in time in my story.


In late 2015 the parking brake snapped and was replaced. In January 2016, a brake spring on the driver side broke and I replaced the pads and hardware. Everything was fine until October. I heard a noise from underneath and thought it was the u-joints. I replaced them on the rear driveshaft but the noise still remained.


So now, I'm thinking it's either the u-joints on the front driveshaft or a problem with the rear brakes or parking brake. I removed the wheel and drum yesterday and saw some unusual wear on the pads. The corresponding witness marks were also in the drum. I've only replaced a handful of drum brakes in my lifetime and certainly not seen this issue.


I looked everything over again and all seems in order. The primary and secondary pads and springs were in their correct locations and the self adjuster worked. I did flip the self adjuster cable where is connects to the anchor such that the crimped end faces towards the backing plate. The images taken were prior to me doing that.


However, the problem still persists. I am going to look at the drivetrain later today, but no doubt the uneven brake wear needs to be addressed. Do you have any inputs as to what can be causing this problem? Could the parking brake be sticking? Any assistance is much appreciated.

BLDTruth

Everything looks to be in order installation wise - my guess is that your drums need to be turned or replaced.

Chap150

What BLD said.

If you haven't, run your fingers on the drum surface facing the lining and you'll feel the corresponding "high" point cutting your brake shoes.

Chap

DFFECHSWU

Yeah, the drums were beat but the previous pads didn't show those wear marks, so I thought it might be something hooked up incorrectly that was skewing the pads in that direction. No matter, though. I replaced the drums and the noise is still there, so further investigation is needed. I think, think, it's coming from the rear but the sound is vague enough where it may not be. I'll follow up when I find the issue.

Chap150

I know it's sometimes hard to describe a sound but from what you mention, the sound led you to think U-joint. So that would indicate a chirping noise. Worn u-joints chirp. But then you go from front u-joint to rear brakes? I'm trying to think that through and what would cause that kind of noise travel.

Regarding drum brakes, front or rear. You will always have uneven wear unless you have the drums turned and shoes ground to match the drum. Not too many places do shoe to drum matching any more. It's possible an inferior shoe lining could cause a chirp on an uneven spot. But probably not. You might hear it for a short while but then it would seat itself to the drum. Worst case is you'd have premature wear on the shoe in that location.

You mention a new emergency brake cable. It doesn't look new in the photo above. There could be just enough tension on the cable to pull the shoe ****-eyed and cause a little noise but then it would stand to reason you'd smell a little hot brake now and then.

I know it sounds silly but if there's anyway to post a sound file you'd have a lot more ears to listen with.

Chap

BLDTruth

Does the noise become more frequent with speed or with rpm?

DFFECHSWU

Thanksfor the replies.


Chap150, I initially thought it was the u-joints based on previous experience andin looking at some postings on the net. They were beat anyway, so the timeto replace them was probably near. The rear brakes and hardware wereinstalled in January and there was no noise until now, so I never gave themconsideration. I see what you’re saying about the parking brake, and I shouldhave been more clear. The portion that was replaced was the section to the pedaland prior to where it tees off to the rear wheels. Those segments were notreplaced.


Evenafter installing new drums a few days ago the noise was still there, so thosemarks like you noted, were made from a previously beat up drum. I have onemore thing to try with the driver side rear. The parking brake return springwas beat up as it went round n' round, and it looks to be setting oddly itsbar. It's a simple enough thing to change, and after I do that, I'm goingto prop the rear and see if I can ID the noise's source. I'll see if I can get a sound file of some sort. I don't have a Go Pro or anything like that but I might be able to get someone to video a small portion as I drive by. We'll see.


BLDTruth,oddly no. It remains constant regardless of rpm. The noise isn’t alwaysconstant either, in the sense that for the most part it’s there but at timesthe trucks is quiet as a whisper. Based on the constant noise when it does appear,I think the rear driveshaft can be ruled out. Same with the brakes, but I’mstill going to clean them up as noted above. Can it be the front driveshaftdoing this? My understanding is that the shaft may spin even when not engaged. Thoseu-joints have never been replaced. I also have the old school system with lockout hubs and floor mounted lever in the cab so any movement in the frontdriveshaft or differential should be limited.

DFFECHSWU

Today I propped the truck on jack stands, removed the tires and drums and let it run in 1st and 2nd gear. The rear drivetrain was quiet. I didn't notice the rate at which the rear tires were spinning. I presume they'd be equal but I could be wrong. I put the tires back on and ran it in 1st gear. The driver's side rear wheel barely moved. It would jerk a bit occasionally but not spin as freely as the passenger side. There was some drivetrain noise, so tried 2nd to see if the driver's side tire would spin and if there was any noise. The wheel moved in a jerky motion as it had in 1st gear but there as no noise. However, there was a fair amount of drivetrain noise forward of the rear drivetrain, particularly after letting off the gas pedal. I have video where the phone is angled towards the transfer case. I revved it 3 separate times and then put it back into neutral. Strange noises indeed. At least strange to me. The video files of all of this but they are too large (40 MB to 115 MB) to post here.

Chap150

By your description it feels like the rear end is doing exactly what it should be doing. The forward drive train noise when letting off the gas would be typical with no load on it. If you like, I have a server you can upload the video to. Let me know and I'll PM you the details. I can then make it public for others to view.

Chap

DFFECHSWU

This problem was solved. Thank you for your inputs. It was a combination of bad u-joints and front wheel bearings. The driver's side front wheel bearing was a big culprit in the noise category. It's sometimes hard to tell where the noise is coming from while driving because you catch up to the noise and that makes you think it's further down the drivetrain. Either way, new inner and outer bearings and seals were needed. Again, thank you for your inputs. This was my first foray into the drivetrain, so it was a bit of a learning experience.