Grinding sound when braking after installing new Half Shafts and removing shims

[johnhjohnson2]

Hey guys,

I took the hmmwv to my buddy's shop today. I replaced both rear half shafts and removed the shims in the rear. There were 2 shims on the passenger side rear and 4 shims on the drivers side rear. I removed all of them as most of the people in post I have read of doing it take them all out. After taking the truck out for a drive I now hear a grinding sound when I apply the break. It sounds something grinding as it rotates not steady like if brake pads were gone. I did not have this issue before replacing half shafts and removing shims. My buddy got under and checked it and said it didn't appear anything was scraping the disc and all the bolts look tight. I hear zero noise when accelerating. Has anyone removed shims or replaced half shafts and had this issue? Thanks for the help.

 

[Dock Rocker]

Where did you get the shafts? The grinding is common with the Chinese knock off shafts.


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[johnhjohnson2]

I got them off ebay. It says manufacturer is MFPC with manufacturer part number [h=2]2520-01-383-2387. Says they are made in USA.[/h]

 

[Dock Rocker]

I am guessing they are not. Just do a little searching on eBay shafts. You will quickly find your answer.

Kascar, hummer parts guy and adventure accessories would be a much better bet.


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[ken]

I assume you are talking about the shims behind the top Arms trying to square the rear tires to the ground. Try reinstalling the shims. Removing them may have taken up any slack. This would make the shafts a little too long and make the joints bind. When you lift the truck to check rotation, the suspension will be farther down. This would make the geared hubs farther away from the diff. So it will spin freely.

 

[Retiredwarhorses]

This has come up numerous times on Chinese rear halfshafts.

 

[johnhjohnson2]

I'm sure that is the issue. The two I replaced on the front are probably the same as I bought them off ebay but I haven't had issues from them when replaced. Again the listing states they are 10K U.S. made half shafts but I don't have way to verify that is the truth. The only time that I hear the grinding noise is when I brake. They are smooth when driving. Is that common with the rear half shafts?

 

[johnhjohnson2]

Hey guys,

I replaced both ebay bought rear half shafts with two american ones from hummerpartsguy. The grinding sound remains. It is loudest when I lightly press on brake. Again this sound wasn't there before I replaced rear half shafts and removed rear shims. Could removal of rear shims cause this issue?

 

[johnhjohnson2]

The left side had two extra shims and we removed them all. But seems to look symmetrical

 

[ken]

Reinstall the shims. Removing them moved the geared hubs closer to the diff. This removed the clearance. They are binding while braking and in reverse. I understand you do not hear anything while driving forward. That dose not mean there is enough clearance. This is also binding the bearings inside the diff. There is a good chance something will break when the suspension compresses while off road or loaded. Also inspect your A ARM bushings. Are they centered with the bolt that goes through them? Are they sagging and allowing the A ARMS to be closer to the center of the truck? Next inspect the diff and housing. Bearings in good shape? Anything broken or cracked?

 

[94M998A1]

Sounds like the same issue I am having. I replaced a halfshaft and then got the grinding noise. Before I bought my halfshaft I confirmed it was a USA made one, I didn’t buy it on eBay.
i reinstalled the old halfshaft and I am still getting the noise so I believe my noise is the brake caliper. I am going to take it apart tomorrow.

 

[Dock Rocker]

Sounds like the same issue I am having. I replaced a halfshaft and then got the grinding noise. Before I bought my halfshaft I confirmed it was a USA made one, I didn’t buy it on eBay.
i reinstalled the old halfshaft and I am still getting the noise so I believe my noise is the brake caliper. I am going to take it apart tomorrow.

A laser temp gage will answer your question very quickly.


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[johnhjohnson2]

@94M998A1Let me know how it turns out. I sure don't want to have to reinstall these shims lol

 

[94M998A1]

I don’t think it’s your shims. I plan on taking mine out

 

[johnhjohnson2]

@Ken Hey Ken thanks for the reply. Everything looks good. The only change is the removal of the shims and new half shafts. Again, I only hear the grinding when I first apply the brakes then it subsides. The lighter I press on the brakes the worse the noise sounds. This didn't happen before I replaced half shafts and removed shims. It seems like a lot of guys here remove their shims and I haven't heard anyone respond with similar issues. Any ideas why it would cause an issue just on my truck?

 

[ken]

@Ken Hey Ken thanks for the reply. Everything looks good. The only change is the removal of the shims and new half shafts. Again, I only hear the grinding when I first apply the brakes then it subsides. The lighter I press on the brakes the worse the noise sounds. This didn't happen before I replaced half shafts and removed shims. It seems like a lot of guys here remove their shims and I haven't heard anyone respond with similar issues. Any ideas why it would cause an issue just on my truck?

Try reinstalling the shims. If it stops then it is binding. If not then something is broken. This will eliminate the possibility of binding. Also remove the brake rotors and inspect them for hair line cracks. Maybe one was cracked during the shaft install. They may have been overheated in the past and might be brittle. Removing them will let you inspect them inside where they mount to the diff. A area you cannot see while on the truck. Also inspect the carrier itself. Pull the cover and look for metal in the bottom. Try to move the carrier looking for slop and bad bearings.

 

[johnhjohnson2]

Reinstalled the shims and the noise did not stop. Again there was no noise before removing shims and installing new rear half shafts. We raised it up on lift and looked and disc and calipers and saw no issues. Braked while on lift and getting wheels spinning and did not hear noise. Sounds like a loud clicking noise now as truck comes to stop

 

[94M998A1]

Reinstalled the shims and the noise did not stop. Again there was no noise before removing shims and installing new rear half shafts. We raised it up on lift and looked and disc and calipers and saw no issues. Braked while on lift and getting wheels spinning and did not hear noise. Sounds like a loud clicking noise now as truck comes to stop

Hey John,
i took my hmmwv to a rearend shop cause I found a rearend seal leak I let him hear the noise and he request all my old shafts, he pin pointed the noise to my new halfshaft and to confirm it was the halfshaft he reinstalled the old stock bad halfshaft and noise went away.
where did you buy your halfshafts? eBay? If not I have heard twice now that it could also be that your truck doesn’t have the correct shims on the input seal plate. I ordered some with my new halfshaft from a different shop since the shop I originally bought from is sold out. I am sending my shafts back to them and they are going to see if they are bad and if not then I don’t know what could be making my halfshafts make the noise except the input seal plate shims

 

[johnhjohnson2]

Well we just put the old half shafts back on and the noise is gone so I guess we experienced the same thing. I am not sure why the new half shafts are making the noise. My first set was a cheap set off ebay, the second set I put on was from hummerpartsguy and were OEM. Both made the same noise. I haven't heard about input seal shims causing that kind of issue but maybe I need to look into that. Hopefully someone who knows will chime in.

 

[94M998A1]

The ones you got from HPG we’re painted carc black even the boot clamps?