SO I believe I posted before that I thought my brakes were sticking........don't think thats the issue.

My rear end bounces....you can see it, and its only certain times...mostly when its hot, or i've been driving for a while (an hour maybe)

I have been taking notes on the symptoms, and finally got some noise today. When the rear end starts to hop it sounds like you are riding on rims and it will actually slow the truck down if you let off the gas.

The brakes aren't hot beyond reason, and I've noticed that it occurs mostly after making a sharp turn???? Or a fast medium turn such as a quick merge.

I think something is either coming loose in the rear or ?????? Not sure

Let me know what you think.

Also, when I pull my camper I haven't had it happen yet.......may be a coincidence.....? Or the fact that I take turns slower when its attached.

 

1999 F150 4.6L ext cab 2wd auto........just for details

 

If you have LS possibly friction modifier may help. If you have a locker or LS it is possible the hopping is the wheels locked (driving you ), does it turn easily or does the front wheels tend to want to slide forward on loose surfaces. Jack up the wheels and turn them/the axle. It should turn freely while in park. If your wheel hop is bad/leaking shocks check em out.

 

I think you are right on point there. I just spoke to a friend of mine who is a backyard mechanic and he mentioned since it happens mostly coming out of turns that my rear locker/clutches are most likely binding and causing wheel hop until it settles out down the road. I am going to pull the cover and clean it out and throw some treatment and new fluid in there and pray for the best. I will let you know when I get it done and see if its fixed......(hopefully)

Another thing too.........when I jack my Dakota up which is LS the wheels spin in opposite directions like an open rear.....I assumed that is because the clutches only engage when a tire slips.....correct?

My F150 is different.....when I jack it up and spin the rear tires they both spin in the same direction.......normal?

 

My F150 with LS axle - both tires run the same way. Normally if they rotate different directions, thats because there is no LS unit and the drive shaft is in park.

 

If you have not taken the rear discs off and looked at the EMG brake hardware, you may be missing the cause.
The brake shoes and hardware totally give up after 150,000 miles even through they were used little.
The lining and metal parts can come free and be subject to physical movements and cause jambing.
This sounds like there was something in the box that moved or fell over and you feel a jerk or binding just as if the rear end gears were 'chunking'.
It's an easy matter to remove the rear axle cover and inspect for debre laying in the bottom and see the ring and pinion and spider gears for damage.
I have just been through this situation.
There are not many places your issue could be between the drive shaft U joints the rear gear and the brake assemblies.
It's likely where you have not looked because we all try to explain it away and miss something in the interpetation until we are forced to look at those areas as last resorts.
.
Here is further info for those who have a problem with brake pulsing that seems to be temperature sensitive.
Some time in the last 6 months, inspection garage had incorrectly tighened the front wheel discs and 'distorted' them.
This puts a 'wave' in the disc than moves with temperature.
Left long enough the cast iron will take a set from the heating and cooling.
The test is to lossen all the lug nut and retighen them evenly.
If the pulsing is reduced or nearly goes awy, you know what the cause was.
If the pulsing does not all go away, it disc replacment time.
A look a them would not show you anything, visually.
Good luck.

 

This is true. Performing a rear brake reline on my brother's F150 I had a heck of a time removing a rear rotor as the park brake lining had separated from the shoe and would jam between the rotor's park drum and shoe.

 

I pulled the cover on the rear diff and there is no metal or abnormal issues. I agree with the brake issue. As far as the rear drums go I still have the hardware kit, so maybe since my shoes themselves look great maybe I will pull them all the way apart and replace all the hardware after I get my rear back together and put some new fluid in it.

Thanks a lot for all the replies. I keep hearing from buddies that "i need a rear end" and I usually don't replace anything that large until I am sure of it. I don't care how much noise it makes, until I find the issue I don't buy parts (usually).

Once I get the rear back together I will check and replace the brakes and let you guys know if I have any more issues.

 

After you get the friction modifier in it take it to a paved lot and turn circles for a bit to get the lube into the plates. Maybe that will help them sticky guys free up. Usually they slip to go out, not the other way around. 2 big/wide a tires and cars would wheel hop in the 70';s

 

I will have to try that. I am so tired from that little job, I can't find my jack handle to let the spare down so I had to work around that

I put the "limited slip" fluid in and almost put 80/90 gear oil in it til I saw the tag said 75/140. I am not sure if that would change anything, but if the problem is the rear I don't want to have any doubts so I put the new fluid in and haven't had time to drive yet. I may be best anyway for the gasket to sit overnight.

We will see. I will probably change my oil and do the brakes tomorrow. I have found out that the rear drums are original shoes, hardware........everything, 165k miles...........so maybe that is a whole other issue as well.

Hit you fellas up tomorrow when I get the rest of the work done and test it out.

Thanks for everything.

 

I agree with Papa Tiger......I do believe you will find that 4oz of friction modifier will work wonders. I had the same issue when I bought my 01 used...It had a leaking rear wheel seal and they replaced it and they forgot to put the modifier in...well...let me tell you..those rear wheels can hop goooood on turns!!...anyhow, what does the door jam code say under the "axle" section?? Does it say H9? If so...you got a 3.55 LS in there...Good luck on your project...