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Noisy Diff?


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#1 Its a min

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Posted 28 March 2020 - 10:10 AM

Morning all.

 

As the title suggests, I appear to have a problem with a noisy diff...or at least that's what I think.

 

The noise sounds like a slight grating/slipping noise and only occurs when moving off from standstill, in first gear and on an incline when accelerating more than usual to get momentum. It doesn't do it when moving  off under normal load, i.e. level surface. When it does occur, it only lasts a split second until the car gets momentum.

 

As a result, the engine came out last year and the engine/gearbox was split. The gearbox was rebuilt last year and all bearings, layshaft etc. replaced. Whilst at it, I also fitted a new clutch and dismantled the diff, replacing the bearings, planet gears, fibre washers and crosspin. The only thing I didn't change were the pot joints/driveshafts.

 

Having removed the pot joints, one of them appears to have slightly smoother spleens. I've ordered a new set from Minispares hoping this will sort the problem but whilst I'm at it, is there anything else I should be looking for/checking?

 

Many thanks for your help in advance.



#2 Its a min

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Posted 28 March 2020 - 06:34 PM

I forgot to add that it does not appear to be the clutch as when i put it in first gear, apply the handbrake and let the clutch up, even with high revs, the car stalls without making the sound.

 

Cheers.



#3 Its a min

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Posted 28 March 2020 - 11:03 PM

Anyone???



#4 DeadSquare

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Posted 28 March 2020 - 11:46 PM

Let's hope the new pot joints cure it.



#5 Spider

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Posted 29 March 2020 - 12:24 AM

If you have lots of Neg Camber (at standard height) and / or Metro hubs and / or worn lower arm bushes, it does put the Pot Joints right on 'that' edge and can do this.



#6 Its a min

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Posted 29 March 2020 - 09:59 PM

If you have lots of Neg Camber (at standard height) and / or Metro hubs and / or worn lower arm bushes, it does put the Pot Joints right on 'that' edge and can do this.

 

Thanks for this info Moke.

 

Standard arms, hubs and new bushes so hopefully should be near standard but will check once the engine weight is back in.

 

One thing I did notice was that the wall of the pot joint, between the drive shaft and the diff,looked like it had been drifted in from inside ending up with some damage and possibly a small hole. It may explain why there was moly grease on the splines. Which by coincidence, and it may just be coincidence, was the pot joint where the spleens appeared to be slightly smoother. Could the presence of grease maybe have caused the pot joint to slip slightly? Guess we'll see when the new ones arrive and are fitted.

 

Cheers.



#7 Spider

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Posted 30 March 2020 - 05:15 AM

 

If you have lots of Neg Camber (at standard height) and / or Metro hubs and / or worn lower arm bushes, it does put the Pot Joints right on 'that' edge and can do this.

 

Thanks for this info Moke.

 

Standard arms, hubs and new bushes so hopefully should be near standard but will check once the engine weight is back in.

 

One thing I did notice was that the wall of the pot joint, between the drive shaft and the diff,looked like it had been drifted in from inside ending up with some damage and possibly a small hole. It may explain why there was moly grease on the splines. Which by coincidence, and it may just be coincidence, was the pot joint where the spleens appeared to be slightly smoother. Could the presence of grease maybe have caused the pot joint to slip slightly? Guess we'll see when the new ones arrive and are fitted.

 

Cheers.

 

 

Cheers for this additional info.

 

The Pot Joints are fairly hard and not all that easily damaged, but they are not bullet proof !

 

Just from your further info, one other thing that occurred to me here it could be is that at some point in time one (or both) of the Pot Joints may have been re-assembled incorrectly.

 

With the shape of the Cage on them that holds the Balls in place, the Balls end up being off-set on the Spider (the part that is on the Drive Shaft). They need to be assembled such that the Balls are off-set towards the end of the Drive Shaft, or put another way, close to the Gearbox (I hope that makes sense).

 

This is a diagram I use to show how the Boot is assembled, so if you can look past that, you can see how the Cage should be assembled on to the Spider;-

 

zt84Uyh.jpg

 

While this shows it all with the Balls pretty much in the middle of the Bell, when in the Car, they are much closer to the outer edge of the Bell. If the Cage is fitted the wrong way around, it does place the Balls right on 'that' edge of the Bell and they can slip as you have spoken of here.

 



#8 Its a min

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Posted 30 March 2020 - 05:23 PM

Cheers Moke Spider.

 

Something for me to check before putting it all back together again!



#9 Its a min

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Posted 08 April 2020 - 10:24 PM

Hi all.

 

So, I've got my new pot joints, arrived all assembled from Minispares, and will be fitting them tomorrow.

 

My question is, should I fit them assembled as they are and if so, onto the driveshaft first or onto the diff? 

 

When I took the old ones off, I cut the cable ties and just withdrew the driveshaft, with bearing cage, from the pot joint so I know I will have to remove the bearing cage from the diff but how will I know if the c-clip is engaged? 

 

Also, how easy should they push on? Having seen the damage on the inside of one of the old pot joints, I'm a little worried that if I have to force/hit it too hard, I could end up with similar damage. Not something I want  to do with new parts.

 

Any advice appreciated.



#10 Spider

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Posted 09 April 2020 - 01:36 AM

I find it easier to fit them on the diff, then fit the drive shaft in to them.

 

Long long ago, I used to separate the Joints by cutting the clips etc, but overall (disassembly / reassembly) I found no time saving in splitting them over just simply removing / disconnecting the Drive Shaft as the Factory Manual recommend. It save loosing Balls, Cable Ties, and that Grease - OH YUK !

 

Separating the Drive Shaft from them is usually an easy job.

 

They usually go on fairly easy. The need a sharp 'knock' to get the started on the Diff. I have a Long Broken Drive Shaft, that I cut the end square on, that I use for getting them started with, slip the Joint on that first little bit of the Diff Output Shaft, then fit the 'Tool' in to that, a tap with a hammer, to get it started over the C Clip, then a couple of light taps until it's home.

 

Then with the Hun fitted to the Lower Arm via the Ball Joint, line up the Drive Shaft with the Inner part of the Pot Joint, while pushing the Hub in, I rotate the Hub Drive Flange, this aligns the splines, then 999 times out of 1000, I find I can give the Hub a reasonable push on the Top Ball Joint, inboard, and the C Clip on the Shaft shrinks, letting it go home all the way.



#11 Its a min

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Posted 09 April 2020 - 05:51 PM

I find it easier to fit them on the diff, then fit the drive shaft in to them.

 

Long long ago, I used to separate the Joints by cutting the clips etc, but overall (disassembly / reassembly) I found no time saving in splitting them over just simply removing / disconnecting the Drive Shaft as the Factory Manual recommend. It save loosing Balls, Cable Ties, and that Grease - OH YUK !

 

Separating the Drive Shaft from them is usually an easy job.

 

They usually go on fairly easy. The need a sharp 'knock' to get the started on the Diff. I have a Long Broken Drive Shaft, that I cut the end square on, that I use for getting them started with, slip the Joint on that first little bit of the Diff Output Shaft, then fit the 'Tool' in to that, a tap with a hammer, to get it started over the C Clip, then a couple of light taps until it's home.

 

Then with the Hun fitted to the Lower Arm via the Ball Joint, line up the Drive Shaft with the Inner part of the Pot Joint, while pushing the Hub in, I rotate the Hub Drive Flange, this aligns the splines, then 999 times out of 1000, I find I can give the Hub a reasonable push on the Top Ball Joint, inboard, and the C Clip on the Shaft shrinks, letting it go home all the way.

 

Hi Moke Spider,

 

You're a star! I knew you'd come to the rescue.

 

It all makes perfect sense but failed today as couldn't get the cages/ball bearings off  the driveshaft. My plan for tomorrow is to remove the whole driveshaft and hubs/discs completely from the car and get the  cages off unless anyone can advise of an easier way without taking the whole thing off.

 

As always, any help appreciated.



#12 Spider

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Posted 09 April 2020 - 06:28 PM

Cheers but then I'm not 'the star' you say I am !

 

I usually find it easy to get them apart while on the car.

 

bJMdKkI.jpg

 

If you land a long heavy Screw Driver (preferably a Tang through type), or similar shaped steel bar, on to the Spider of the Inboard CV as shown with the red arrow and give it a sharp tap or 2, it should come apart. In this photo, I've already just disconnected it.

 

This is how I disconnect the Drive Shafts from these Joints, when say, removing the engine.



#13 Its a min

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Posted 09 April 2020 - 10:14 PM

Thanks Moke Spider.

 

Big screwdriver at the ready!



#14 Rorf

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Posted 10 April 2020 - 05:03 AM

Some times these cages will just not come off the shaft. You can hammer them, pull them, heat them etc etc but 40 years of permanence will not budge them :D



#15 Its a min

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Posted 10 April 2020 - 06:45 AM

Some times these cages will just not come off the shaft. You can hammer them, pull them, heat them etc etc but 40 years of permanence will not budge them :D

 

Thanks Rorf, I like a challenge, that's why I have a mini!  :D

 

I had them off a few months ago, whilst everything was off the car, and changed the rubber boots. I applied copper grease before refitting them so hopefully, a little tap with a big  hammer, or a big tap with a little hammer, should get them off.

 

Fingers crossed!  :o






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