Axle shaft knocks into hub, What is the reason? Options

[ruby914]

A long time ago, I started to get a knocking sound when I accelerated from a stop. At first I was worried but far from home there were no other problems so I just got use to it. I have been driving it like this for some time now. Now its time to fix it. Sounds like my axle shaft is knocking into hub. I just pulled the Inbd CV and the C clip is on the axle. Before I pull the Outbd CV, I thought I would ask what I should be looking for. Any thoughts?

[BigFour1973]

A long time ago, I started to get a knocking sound when I accelerated from a stop. At first I was worried but far from home there were no other problems so I just got use to it. I have been driving it like this for some time now. Now its time to fix it. Sounds like my axle shaft is knocking into hub. I just pulled the Inbd CV and the C clip is on the axle. Before I pull the Outbd CV, I thought I would ask what I should be looking for. Any thoughts?

Check your transmission mounts, it sounds like its tilting and bumping into the metal.

if thats not it check the motor mounts and see if they are still intact

[ruby914]

A long time ago, I started to get a knocking sound when I accelerated from a stop. At first I was worried but far from home there were no other problems so I just got use to it. I have been driving it like this for some time now. Now its time to fix it. Sounds like my axle shaft is knocking into hub. I just pulled the Inbd CV and the C clip is on the axle. Before I pull the Outbd CV, I thought I would ask what I should be looking for. Any thoughts?

Check your transmission mounts, it sounds like its tilting and bumping into the metal.

if thats not it check the motor mounts and see if they are still intact

Motor / transmission mounts are all good. I can push and pull the axle shaft in and out and recreate the knock. Even after pulling the Indb CV I hear it by hand hitting something?

[BigFour1973]

maybe check out the suspension pick up points? check the top hats of the springs for rubber bushings or lack there of. see if theres play in the rear trailing arm.

Other then that im out of guesses.

[76-914]

Bad CV. Where you been?

[stownsen914]

In my 914 racecar I have this issue. For years I used stock 914 CVs. I'd see light polishing on the tranny output flanges where the CV cages or balls were contacting the flanges. No damage, really, just light contact that polished the flanges a little. I don't think there is anything loose in the suspension, so I assumed this was caused by natural movement back and forth of the CVs, either from side forces in turns, or perhaps from some thrust forces that happen when power is applied through the CVs. And there is plenty of side to side slack with my axles throughout the suspension travel, so I don't think the axles/CVs were being mechanically forced into the flanges.

A couple years ago I tried Empi beetle CVs (required machining to fit) since 914 ones aren't available anymore. The thrust forces seemed to get much worse with the Empis. After only a short time those light polished areas on the output flanges became machined divets. I assume the Empi joints are designed differently and somehow there were greater thrust forces. I switched to Lobro beetle CVs, and so far, so good.

Scott

[Cracker]

I guess I don't understand. From your description, as I *thought* I understood it - it sounds like your spindle nut is not fully tightened. Again, I might be off base with what you are describing.

Tony

[ssuperflyoldguy]

new here as a 914 mechanic but maybe bent swing arm or bad cv

[Larry.Hubby]

It may be your CVs just need re-packing with grease. When my car was fairly new, I remember a mechanic checking the CVs with the car up on a lift. He just grabbed the half shafts and tried to move them in and out. One didn't make any noise when he did that, and the other knocked like you describe. He said, "We better re-pack this one with grease. If you let them go like that, they'll ruin the CVs and maybe the stub axles." He re-packed it, and it was fine. Years later, an axle began to knock when I accelerated from a standing start, sounding the same way. I remembered the previous diagnosis and had the axles re-packed. Problem solved.

[Frankvw]

I agree with the repacking and also check the CV in general...all bolted up OK ? My friend has a VW T2a where we installed an IRS trans in the lowering project....same symptom...CV bolts were loose and came more loose after some miles driving.

[ruby914]

Thanks guys,
after Stownsen914 reply I felt just repacking may be all it needs, to slow down and dampen a normal condition. I had to go to work so I still haven't pulled the Outbd CV yet. Larry and frank confirmed this thinking. I have a set of CV that came off my suby car so I will replace the Outdb CV with one of those, freshly packed units.

PS, Hey Kent (IMG:style_emoticons/default/driving.gif).

[whitetwinturbo]

...............how about a link to the "repacking" thread (IMG:style_emoticons/default/beer.gif) (IMG:style_emoticons/default/beer.gif) (IMG:style_emoticons/default/beer.gif)

[76-914]

Well I'm glad your driving it. I still remember you "launching" us onto the freeway from that uphill entrance. What a kick in the (IMG:style_emoticons/default/bootyshake.gif) . (IMG:style_emoticons/default/beerchug.gif)