88-F150 4X4 Front End Clunks

Yep, I got the answer. :) Stop looking and start feeling for the problem! ;) Get someone to make it clunk while you're under it and feel of all the moving points in the system. And, while you're at it, quit assuming that since something's new it's not the problem too, ok? In other words "know". :)

The problem is right there waiting for you to find it.

Funny thing is tho, with all that messing around, checking stuff out "under there" you'll prob'ly find something else that isn't quite right, that you'll want to fix too. Cool huh? ;)

Alvin in AZ

Thanks Alvin...

I have been under there and can't seem to trace the problem, will I need to be on a hoist to effectively check this out?

I have had someone turn the wheel while under the truck on the ground, I can't seem to find it.

It was suggested to check pivot Bushiings.. what can you tell me about that?

Stu, Vi.BC.CA

Might help, what exactly do you have to do to make it clunk?

So it doesn't clunk all the time, it's intermitant?

Nuttin' I ain't that smart. :/

Alvin in AZ

Pivot bushings are the ones on the ends of each axle. "opposite the spindle". I guess one could clunk, but seems to me, looking at them, that if a pivot bushing went bad you would have a binding or popping noise rather than clunking. Have you checked the kingpins? Wheel bearings? Brake hardware? It would help to know what action makes it clunk. IE: rocking forward and backwards, or only when turning, etc... Makes sure the shocks are tight at the top mounts. MK

I replaced mine, they looked like hell! But there was still plenty of dammed good rubber inside of them. (took the old bushings apart after they were replaced) Oil will kill them deader than anything I know of, my son's '71 was without rubber on the side where the power steering pump leaked on it and the other side looked fine.

And -see- that it's not lined up worth anything too. :)

Yeah what MK said. ;)

Could it be described as a rattle when you go over something rough?

Alvin in AZ

I have bought new shocks for the truck, and I am going to replace them all... It doesn't "rattle" when going over bumps, but will 'clunk' over some of the larger ones.... Whenbraking sometimes there is a clunk or when cornering on a slow curve (Either way) it sometimes clunks.... I have so far been unable to reproduce the sound when under the vehicle... So finding it has been difficult, I am going to try lifting it on both sides so there is no weight on the wheels but the axles still bear all the weight... Not sure what that will accomplish but it was another suggestion by a local fellow... To do that and turn the wheels slowly to their max either way...

Thanks for alll the suggestions and info, I keep struggling to figure this one out...

Stu, Victoria, BC. CA

Well it's something "big" I figure, like the king pins or pivot bushings.

The king pins and their bushings were in pretty good shape when I replaced mine but the end play was close to 1/8". The weight bearing, thrust bearings were pretty badly worn. Mine (1/2 ton) were a combination of a thick hard brass washer and a thick, hard steel washer with an extra high carbon steel case (2% carbon?). Since then I've found some old Ford pickups have a thrust bearing with radial neddle bearings in a round case.

Your's might be wornout in both directions, up-down and side to side.

I re-read the first post and you mention it sometimes clunks while stationary and turning the wheel?

It seems to me you are going to have to figure out how to make it clunk while you're under there so you can find it for sure and stop guessing. Then there's the shotgun approach "when you don't know what's wrong... make everything right" -railroad signalman

It sure as heck won't hurt anything! :)

The more fiddling with it you do the more you'll know about the system, next thing you know you'll be answering questions about it here. That's exactly where I'm coming from. :)

You are going to find it ...if you don't give up.

The rattling I asked about would have been easy! At the dealership (in '75) they took the anti-rattle clip/spring out of the driver's side brake pad. I figure they did that for warranty work money. :/ There were a few other sneeky tricks they pulled too. They are out of business but it was called "Johnson Motors" shoulda known huh? ;)

Alvin JohnsTon in AZ

Sounds like the axle pivot bushings (since you've already replaced the radius arm bushings) need replacing. These are the bushings that the axle halves attach to the crossmember with and are of course considerably more difficult to do. Go with poly bushings there too. Randy

|The king pins and their bushings were in pretty good shape when I |replaced mine but the end play was close to 1/8". The weight |bearing, thrust bearings were pretty badly worn. Mine (1/2 ton) |were a combination of a thick hard brass washer and a thick, hard |steel washer with an extra high carbon steel case (2% carbon?). |Since then I've found some old Ford pickups have a thrust bearing |with radial neddle bearings in a round case.

Moog used to offer kingpin bushings in 2 or 3 varieties - Bronze bushings, nylon bushings, and maybe a 3rd option. A lot of mechanics used the nylon because they were easiest to install and most tolerant of wear.

Rex in Fort Worth