Possible rear CV Joints need help

[rekstein1]

Help Guys! 1988 911 Cab that I pulled out last week to drive this early spring.
First week no problems was on the way to a great summer. This week inside the cab it got very loud. Had to turn the radio up to hear it decently.

Wife got in the car this past weekend and said it was loud inside and that something is wrong. Brushed it off and today it got louder.

It seems to be coming from the rear. There is some vibration at 50 mph and higher and just a loud noise as well . It get less loud as the speed decreases down to 30 mph. Can barely hear the engine inside the cab like before.

Crusing along at 50mph took the car out of gear and there was the sound it was just loud and seemed to be in time with the rotation of the wheel. Did the slalom thing up and down the road with the car out of gear and heard nothing.

How does one check for bad CV joint in the rear? Anyone have any thoughts or encounter this? Where do I start looking for the sound?

Was going to put the car up on jacks and spin the wheels to see if I hear something

Your thoughts welcomed

[Jeffreypang911]

Jack it up and check it by spinning the wheel, maybe you blew a cv joint in the rear. Its happened to me before!

[yelcab1]

If it is that loud, you should be able to hear it with the car in the air an spinning the wheel.

[rekstein1]

If it's a cv issue buy the whole axle or repair the one I have?

[Joe Bob]

https://www.facebook.com/groups/284744841583679/

Joe A has axles and CVs for sale.

[Bill Douglas]

While you have the car jacked up to check the CV joints; check the gearbox oil while you're at it.

[T77911S]

could be a wheel bearing.
to me bad bearings sound like what I think a "dry" bearing would sound like. kind of a "rough" sound.

most CV joints (other cars) I have heard have a clicking sound. the higher the angle a CV joint has the louder or worse it will sound. like a front wheel drive car. fairly quiet going straight but turning they are extremely loud.

with that said, I would think a 911 CV would have to be extremely bad for it to be really loud because the angle on the joint is not that extreme. just a speculation since I have never heard a bad 911 CV joint.

check the boots. if any are torn and no grease, that's not good.
the other you can do is
what I did on my 930 was jack one side just enough to get the wheel off the ground. start the engine and put it in gear. let the clutch out slowly and unless you have an LSD, it will spin one wheel. you can do each side.
be very careful if you do this.

my bet is a wheel bearing.
they were so bad on a BMW I bought you could not even talk in the car it was so loud.

[Duc Hunter]

Just a side note look at the tires too. I had this happen once and realized the tires we worn in a fun way. In my case, for some reason, the tires over a winter just decided to give up. When I started driving in the spring they wore really fast and changing them made the car quiet again. Just a thought, though it sounds more likely to be a CV.

[AC78]

Apologies for thread hijack, but what is the general consensus on replacing CVs - renew existing hardware, or purchase new CV and axle assemblies from Pelican?

I enjoy wrenching on my car but repacking CVs looks like a horrible job. Also my CVs and axles are near 40 years old now so am leaning towards a whole new assembly.

Would be curious to hear other people's thoughts on this.

Cheers

[Joe Bob]

Dirty filthy job repacking them with grease. High failure rate. New CVs and axles are the fastest way to go. PP used to sell them, my last replacement was thru Eric at pmbperformance.com.

EDIT: To clarify, now that I have had my coffee and BP meds....the CVs and axles are one pre-built component for each side. They are a simple swap with the need of a few small easily obtainable tools bits. If you are a competent DIY person easy. If not a search will find many threads and hints on the subject. If you need a hand, many PP members have been known to drop by and help. I am willing to discuss on the phone with you if needed.

CV failure is predicated by a clicking sound. Bearing failure but loud whirring noise. If not sure, most independent alignment shops will give an opinion on the subject and an estimate for repair. Since I do my own repairs, I have no idea what a shop would charge for parts and labor.

CVs can fail with an intact boot due to high mileage, a torn boot that spews out grease or just age. Don't go with the cheapest CVs as you will likely re-visit the replacement again soon. Not rocket science to replace but there is a significant grunt factor involved and some tricks if the Castle nut hasn't been off in a while or you drive in a snow and rain environment.

Bearings, there are cheap and more pricey bearings. They can be a bear to remove, read up on the R&R of them. Be advised, swearing can be involved, there is more than one way to remove them, consider renting or borrowing the "right" puller. Be advised that the hub race can be damaged if the bearing is really far gone. YES, Use the freezer on the new bearings to aid in easy slip in. Do not force them in. They can be damaged in installation. Easy is good, force is bad.

CVs can be rebuilt, repacked and reused. But CV grease besides transmission fluid is one of the nastiest "used" fluids known to mankind. The smell and the feeling on my hands, even with protective gloves, just sets my teeth and nose into flux. After all the grease/fluid IS a hazardous material of a sort. Designed to handle high heat and can't be a good thing to be in close proximity to. If you insist on tearing the CVs down, be advised that the ball bearings, the cage, snap ring, boot, outside fasteners are like a Rubik's cube. I'd rather deal with Quantum Mechanics while listening the Rush Limbaugh and the dittoheads sing "OH Tannenbaum".

Good Luck, report back.

[Franks89-911]

Originally Posted by AC78

Apologies for thread hijack, but what is the general consensus on replacing CVs - renew existing hardware, or purchase new CV and axle assemblies from Pelican?

I enjoy wrenching on my car but repacking CVs looks like a horrible job. Also my CVs and axles are near 40 years old now so am leaning towards a whole new assembly.

Would be curious to hear other people's thoughts on this.

Cheers

I replaced one when I found a boot had been torn sometime during Dad's life/ownership. I don't have the time, knowledge, or capacity to disassemble, repack, etc., and not knowing how long the car had been driven like that, a simple replace was my choice. All I had to buy was the 32mm socket for the wheel nut and an 8mm hex nut for the bolts on the inner side. Maybe 1-2 hours labor per axle. Surprisingly easy. Hardest part was getting enough Newtonian force on that wheel nut to get it off.

[Jesse16]

I like the idea of a bad wheel bearing myself. Usually described as a howl or growl noise. If the CV boots are still intact and no outside grease is visible then its unlikely one is bad enough to make a constant noise. As others say, you should be able to diagnose with wheels in the air and turn by hand. Take a good look at everything. If you have a bad CV boot, whether to buy the rebuild kit from our host (grease, new boot and clamps) or buy new is simply your interest in a messy project and cost saving.
You also have to buy or borrow the tool cinch the pinch clamp. I rebuilt mine after boot tears and they continue to work fine.

[charwood77]

My bet is wheel bearings. When my rear bearings went bad it sounded like I was piloting a cesna.

[Joe Bob]

Depending on the tubs mileage a CV AND bearing replacement would be good idea while you are in there. Mine failed on both sides within 500 miles as I have an LSD transmission and had a high HP motor swap and tracked the car.

[McLaren-TAG]

To the OP, it helps a ton when you describe the type of sound. Just saying it's loud is why you're getting the scattershot of responses.

CV joints do make a wooing sound especially when under larger angles like going through a slalom. Bearings make like what was described, a loud bearing sound. Have you gotten under the car to look? Have you lifted the car up and spun the rear wheels to see if there is noise and where it's coming from?

Most of the stuff back there is easy enough to fix but one thing you said worries me... you heard the sound and just ignored it. That's never the right thing to do, it never ends well and the more you neglect things the worse they get.

[T77911S]

CV's are pretty robust.
messy job might be an understatement. just did all 4 on my 930, boots and grease that is.
they also need to go back together a certain way. that is the inside cage needs to go back in with relation to the outer part.
then the CV needs to go back on the axle the correct side out.
its not hard, just messy.
I would definitely replace all the washers. bolts are up to you as long as the ones in there are the correct length. 2-3 threads should stick out past the flange.
threads also need to be clean.
you DO NOT want a joint coming off while driving.

you can get bolts and washers from Fastenal. bag of 50 is still cheaper than buying the correct amount individually. they also come in 5mm lengths.

boots are another issue.
just saw a post about an alternate boot than original.
also, you can get the pliers to clamp the original type clamps at advance for about $10. .

did I say it was messy

[Luccia at Pelican Parts]

I've had wheel bearings exhibit some really strange symptoms and sounds before. How many miles are on your current ones? As the mileage increases on the car, heat and lack of lubrication can cause the bearings to wear and possibly fail. I have even had a few that don't have the typical howl/growl sound or weren't very pronounced when putting load on one side. If you're savvy enough and can grab a video of the sound it might help a bit. Also, I have seen vibration be contributed to bad axles before. Otherwise, lots of great advice given already on how to diagnose the issue. Let us know what you find out.

If you do decide to replace the bearing - FAG, SKF and Genuine are all good brands to go with: 1988 Porsche 911 Carrera Convertible - Axles, Bearings & Differential - Page 5.
If you do decide to replace the axle - GKN is the OEM supplier and I've had great success with them personally. Otherwise we have Geunine as well - 1988 Porsche 911 Carrera Convertible - Axles, Bearings & Differential - Page 1

[rekstein1]

Tuesday's update: Got the car jacked up and spun both rear wheels individually. No grinding sounds, wheels seem to spin seemingly freely. Looked at the axle boots no grease anywhere , no torn boots. Current Mileage since it was asked is 150,000k. Got the car at 110,000. No great paperwork before this.

I saw a post where it was suggested to jack up the whole back, start the car and run the wheels. As the author suggested this is risky. NOt up to doing this as I don't want to do body work on the hood.

Barring any other tests anyone can suggest I think its time for a professional look.


Anyone have any suggestions?

Didn't check the front wheels as I think of it. But I could swear the sound was coming from the rear. Will check the fronts tomorrow as it is dark now

Appreciate any thoughts

[Bob Kontak]

Originally Posted by rekstein1

Barring any other tests anyone can suggest I think its time for a professional look.

Was the car on jack stands and did you have your hands on the wheel drive shafts feeling for anomalies while you spun the wheel? Or, did you jack one side up and spin the wheel from the outside?

[T77911S]

I have done both.
had car on jack stands and ran it in 1st gear.
also put a jack under one side and ran it.

other option is to remove the wheels and pull the brake pads out and turn it by hand. you may be able to feel or hear it.

take to a shop and let someone ride with you.
a mechanic should now what a bearing sounds like.


like I said, CV's are pretty robust, with the boot intact and with the low angle on the joint, its probably the bearing.