Ok well for some reason, whenever I'm moving and I tap the breaks, I hear a loud thumping noise come from under the truck. It's only right when I hit the brakes, and doesn't happen at all while I'm driving normally or after initally pressing the brake pedal. At slow speeds it seems a little quieter. It doesn't seem to be coming from one side or the other, but rather from in the middle of the truck. Do you think its the front driveshaft? I don't know why it's only doing it when I brake though. The front driveshaft is all I can think of because I don't have the Superlift shaft yet, so perhaps this is the vibration they're talking about? Any other ideas as to what it might be and how I might be able to fix it?

 

I know exactly what it is.....There is a TSB on exactly what you are describing. its the slip yoke. If your truck is still under warranty go to the dealer and will fix it under warranty. It is nothing serious. The fix it to disassemble the slip yoke and clean out the old grease and replace with a thicker motorcraft grease. The splines have a bit too much lash and you hear the thump under braking and acceleration.

 

hes out of warrenty..... that sucks bro....

 

looks like you need that new drive shat from superlift.

 

The slip yoke issue is not a "loud thumping noise"; in fact, it is not a noise at all. It is a single bump usually felt through the driveline on initial accel or sometimes when coming to a stop.

 

when you let off the gas or right when you touch the brakes?

 

It can happen any time during deceleration or braking when the torque across the slip yoke spline is reduced enough to let it slide. With new grease, it is more slippery than with old grease and it may not bump at all.

On the Rangers I have driven, the slip yoke bump is much more noticeable on initial acceleration that it is when slowing.

 

no i was talking about kyle's problem. i thought we decided that prolly wasnt it.

 

Ok actually I found out what it was... Get ready for this one.






My brake caliper was about ready to fall off. Somehow the bolts on the right side brake caliper managed to wiggle themselves loose from 50 ft-lbs of torque. The top one fell out entirely, and the bottom one was on its way out. My guess is that when the brakes caught the rotor, it would slam the caliper into the rotor, making the thumping noise. I tightened down the bottom bolt and it went away. I'll have to go to the dealer tomorrow to get another caliper bolt. On my way home from work tonight i heard this bad rattling coming from behind the right wheel right as i pulled onto my street. I think the last bolt could have gone at any time. It's a damn good thing it didn't...

 

In my 2002 shop manual, the torque for the bolts that mount the caliper assembly to the knuckle is listed as 85 lb-ft. When new, the bolts may also have had a threadlocking compound applied to the threads. I have seen this problem posted before but never for bolts that have not been disturbed since leaving the factory.

 

Oh, well my bolts got disturbed when I installed the superlift. The instructions on the lift said something like 35-40 ft-lbs though, so I figured 50 would be a good bet. The passenger side ones are in just fine, havent budged. I'm going over to the dealership now though to get a new bolt, I'll be sure to torque them up a little bit more. Talk about a scary encounter!

 

glad you figured it out kyle.

 

Them bolts bring back some bad memories. A few years ago I just had the brakes done at a local big name shop. I was driving around after wards when all I hear is loud constant clanging noise coming from the front end, the truck would barely move. I take it back to the shop and they said the caliper bolt fell off and ht ecaliper was just hanging there by the brakeline. I was a little poed. Then to top it off the bolt is a Ford specialty bolt and they had to have one made by a machine shop to replace it, the local Ford dealer had none in stock. 3 days later the truck was fine again.
Sorry about the hijack.

 

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