Hello

Hoping for some advice

I just picked up a 1972 914 PO said it was solid and brakes were good

Got it home and it ran fine

Now it has developed a knocking or clacking sound from passengers rear wheel
at low speed under load increasing with speed

Once the car is over 40 MPH it fades away

Also when I depress the clutch sound goes away

I took off the rear wheels no stones or nails
Also swapped tires no change

CV joints are 5 years old and no leaks or cracks
Bearings are 5 years old as well


I noticed rear brakes were worn down almost to the metal on the wheel making the noise

I surmised that perhaps the rotor was a little warped and as it rotates hits the wear indicator built into the brake-pad

To test this I applied 1 squirt of Lithium grease to the rotor

The noise when away for 10 miles but slowly returned

Do you feel it is the brakes and not the CV or Bearings??

Thanks

MIke

This is what I would do given what you have described.

1. Replace all the brake linings ...check the rotors for wear and runout. The specs are in the Haynes manual.

2. Inspect the CVS for wear and regrease.


PS. Not a good idea to put grease on your brake rotors and drive around that way.

My .02.

Thanks for the advice

Yes I agree I only applied lube to 1 wheel to test

I will change out the brake pads

If any grease is applied it should be to the edges of the pads where it contacts the caliper and the retaining pins (lightly) so that the pad floats evenly back and forth rather than getting hung up and clacking against the rotor face.

Any more comments?

Should have bought my car when you had the chance.

Thank You Rob for your constructive advice

Well


I replaced the rear brakes pads (this was needed) and inspected the cv joints they are clean boots are in good condition and move side to side freely

The clacking is still there

Any Ideas anyone?

In your first post you state that after you applied grease to the rotor, the noise went away.

So did you check the passenger rotor for wear and runout?

Also a bent rim comes to mind.

"Klacking" to me describes a bearing noise.

Checking the CV's involves more than the boots. It involves removing them and inspecting the actual races. It is a really nasty job so make sure it isn.t something simple first.

I did not check the run out

Would I need to buy a dial indicator?

Also I noticed I drove into an empty parking lot

I turned the wheel all the way left and hear clacking

then turned the wheel all the way right no clacking

CV Joints

I will borrow/Buy a dial indicator

thanks

Make sure the hub nuts are tight first. Also check tje bushing condition

Thanks for your helpful advice

Back up, does it click louder?
Cv joints click when dying.
It's a 40 year old cv joint

... Yeah, it sounds like your right CV joint is going. They shouldn't be 'clean' (unless you've just de-greased them for checking and prepping for reassembly) ... they should be smothered in grease during the reassembly process.

Pull all of them, check the components and do whatever needs to be done. Cracks in balls are not good. Worn cages are not good either.

I believe new/rebuilt joints are still available ... but this is a ten year old thread: Click here

Type 1's are still available.

Chris Foley at Tangerine can set you up.

I also know PMB can drop ship Lobro's out as well, however Chris machines a nice recess in them for the gaskets.


If you determine that it is the CV's....I'd pull both half shafts and do them all. Not that big of a deal....just messy.

Still doesn't make sense that the lithium grease had any affect?

The cvs are important anyways but take a 2x4 and stand it up to the rotor. Balance anything on it (another 2x4, screw driver, ruler is best). Put the edge close to the rotor and spin the rotor while watching the gap
Run-out will show with a flash light

Did you measure the venting clearance to the Haynes spec or correct spec?

Then when your checking the cv's. Check the bearing, hub, console and bushings too

I lost my half shaft doing 70+ up hill. It clanked like that on the pass side a few times warning me. On the rear, I believe its a big king nut and a king pin.

Years ago, I looked at a '65 912 up in the local desert - the passenger-side outboard Nadella shaft joint failed and I was shocked at the damage it caused to the car

Thanks for all the suggestions


I will check the run out

Also I noticed the hub nut was not tight

Also swapped rear tires to see if it was a rim issue...no change in sound

Im getting a torque wrench I believe the spec is 200LBS

The clicking does not occur in reverse nor doe it happen when I depress the clutch

Thanks and I will try to tighten the hub nut and re-inspect the CV joint

The big castle nut? Good thing you caught that. That thing is supposed to be TIGHT with a cotter pin in the hub. Looks like you have the spec needed. Basically the hole for the pin becomes visible between the spaces in the nut so you can thread it through. That's when you know it's tight enough. I'm pretty good at breaking CV's and they aren't very tolerant if bad and under load. They could need some lube. If the hub tightening doesn't fix it then it could be the bearing on that side .

That sounds a little light, IIRC. Isn't it something like 280 ft lbs

It's "stand on a breaker bar at the end" for me .

Not quite that much. Spec is 217-253 ft/lbs. I personally like to take my torque wrench to near max, which if I remember is 180 or 200 ft/lbs. Then turn the nut a little more, just enough for the first "slot" in the castle to accept the cotter pin. That should be right in the ballpark. In theory, you shouldn't really be able to over torque these types of bearings, but it's not necessary to get them on there with more torque than specified. What definitely can ruin them is not being torqued enough, i.e. less than 150 ft/lbs.

Hello

Swapped out the CV Axle all is good

Thanks everyone