Jump to content
RogerH

Dodgy clonk at the back end

Recommended Posts

Hi Graeme,

                 nice one. I shall get new washers and pack out the SuperPro supports.

 

Roger

Share this post


Link to post
Share on other sites
10 hours ago, RogerH said:

Hi Folks,

                the diff is back in. The SuperPro diff mounts are fitted. everything is buttoned down.

On the test drive the clonk of last week has reduced a good amount but there is something still there.:angry:

 

I'll take it for a long run when the weather dries out a little and see what is going on.

 

Hmmmm

 

Roger

H Roger,

Did the diff rebuilder comment on what if anything as wrong with your diff?

Alan.

Edited by AlanG

Share this post


Link to post
Share on other sites

Hi Folks,

              we are now at the beginning of the end.

I dropped the diff out today and removed the rear cover.  Cleaned the oil out. Checked the backlash of the crown wheel/pinion. 

It should be 0.004" (0.1mm) - deep joy mine is 0.010"+   (0.25mm). 

So it would appear there is a problme with the position of the pinion.

Tomorrow I shall make the unpinching frame and remove the the crown wheel assembly and check the height of the pinion - I hope it is 0.006" too low or there abouts.

Roger   

Share this post


Link to post
Share on other sites

Roger,

I don't know whether you have now sorted your clonk- I have come a little late to your query.  However, I had the same (or a similar?) problem a couple of years ago, that sounded as if a flange was insufficiently tight on a shaft and moving under torque .  It first began when starting from rest on full lock, but got gradually worse with time, until it occurred on hard acceleration and on the overrun but importantly, initially it required significant torque for it to occur, to my mind ruling out worn splines.  Having checked the tightness of the input and output flanges, in desperation I had the diff overhauled, and that cured the problem initially, but it is back with me now after about 3000 miles, starting in the same way of initially requiring significant torgue for it to occur.  The company that did the overhaul diagnosed an input flange moving on the tapered portion of the inner half shaft, the clonk being the flange hitting the key in the inner half shaft.  I was told it was a fairly common problem with the 4A and the only solution was to have the two items separated (for which a press is required) cleaned, a new key fitted and reassembled with the correct torque loading.  I have assumed that this diagnosis is correct and have decided to live with the clonk, certainly until it gets really worrying!  Hope this helps!

Geoff

Share this post


Link to post
Share on other sites

Hi Geoff,

             I have considered all the bits and pieces around the diff. And have not found anything to indicate that it is not the diff.

I had thought about the two drive flanges that attach to the drive shafts but have discounted tham as the clonk appears to move left and/or right across the back.4having found excess backlash on the crown wheel I am concentrating on the pinion packing.

I now have the crown wheel out and am looking up the dimension that the pinion rear face is set at.

I am following ed-h's rather good explanation of it all but he does not give this dimension. But he does have a link to another site.

 

Roger

Share this post


Link to post
Share on other sites

Roger, I have a diff setting tool that would make checking your pinion depth a breeze. The question is how do I get it to you?

rgds Ian

Share this post


Link to post
Share on other sites
1 hour ago, RogerH said:

I had thought about the two drive flanges that attach to the drive shafts but have discounted tham as the clonk appears to move left and/or right across the back

Are you sure there is no one locked in the boot!:o

Share this post


Link to post
Share on other sites

Where is Sue now that we need her?

Share this post


Link to post
Share on other sites
4 hours ago, Ian Vincent said:

Roger, I have a diff setting tool that would make checking your pinion depth a breeze. The question is how do I get it to you?

rgds Ian

HI Ian,

 

I think I now know why I have too much crownwheel backlash - fear !!!!!!!!

             I have 0.006" too much crown wheel backlash. So I need to move the pinion X thou rearwards. 

Because of the angle of the teeth I am going to insert a pair of 0.003" shims under the rear bearing outer cup.  This may well not equate to 0.006" rearward movement of the pinion but will be a good start.  It has taken me about an hour to understand where the shims go.

Interestingly there are no shims for the preload !!. 

On a another point.  The rear flange that attaches to the propshaft slides onto the pinion splines quite easily with both parts in my hand

However with the pinion in the casing the flange has to be hammered fully on.  !!  rather odd.  More understanding required.

 

Roger

Share this post


Link to post
Share on other sites
37 minutes ago, Waldi said:

Where is Sue now that we need her?

Don’t worry, he will let me out when he needs to get the car off of the ramps.

Share this post


Link to post
Share on other sites

Rodger, f,git about the pin height on a olde/worn diff

cos if teeth on both are used  /worn,     wot good is a pin height guide,!!!

 

Yer CW maybe needed t,be set with that much pree load, as some teeth maybe touching at a lesser load.

quite common i fin on thee,s, the Spitty type are even wuss for this,

 

Ye need t,see how easythe pin moves in carrier, if its just spinning, its no got any pree loadings

its just nee good fitting shims, as fit,n shims onto Pin only will move contact point aboot

6 thou is ALOTT t,add, whenst diff should have been set up.

Altering the sideways movement { shims } has a bigger effect,

but will also alter the contact patch

 

ye need some Dykum blu, and really need t,blue it up

and t,see ALL teeth patterns, ye need t,blue all teeth

just a few teeth dont give a full picture.

wid the thing under a loading too, ora wrong reading will be shown

 

rgds M

Edited by GT6M

Share this post


Link to post
Share on other sites

Hi Marcus

          thanks for that. I'll fit the shim under the pinon as a first step and see what starts to happen.

I'm in no rush so plenty of time to see what does what. 

 

Roger

Share this post


Link to post
Share on other sites

Hi Roger

would you like the loan of a diff to fit and remove all the doubt regarding all other moving parts.

 

Roy

Share this post


Link to post
Share on other sites

Hi Roy,

 that is very kind of you. 

First I will get this one rebuilt and fitted and see what happens. If the clonk is still there then I may well take you up on your offer. Leigh-on Sea is worth a day out.

Even after rebuild it may still be duff (two experts have shown me that) and the chasing of tails continues.

I replied to Rod this morning and finished of by saying  - there are only three adjustments.  What could possibly go wrong.

 

Roger

Share this post


Link to post
Share on other sites

Hi Roger,

Marcus knows way more about these things than me but you may find the gauge useful to get the pinion in approximately the right position before checking it out with engineer blue.  Also to avoid the faff of having to pull the pinion bearings every time you adjust it, I had a friend turn down a scrap pinion so that the bearing was a sliding fit then I could swap it in and out much more quickly.  That's the recommended procedure in the w/shop manual although they point out that because the bearing is not under tension when it is installed you need to allow an extra couple of thou to you shim pack to compensate.

Attached are a few pictures of the diff gauge and contact pattern for my diff.

The difference between the First Setting and the Final Setting involved removing about 2 thou of shim to move the pinion further away from the centre line of the CW.

Also on Marcus's advice I set the whole thing up with quite a lot of preload although after 1000 miles, (I don't do the sort of mileage you do), most of that preload seems to have gone.

The axle has been absolutely silent so I guess it can't be far off.

Rgds Ian

PS With regard to your comment about no shims on the preload; to get the right preload on my pinion, I had to remove all the shims from the pinion spacer so if I ever need to tighten that up, I guess the spacer will need trimming on a lathe

Pinion Gauge #1.jpg

Pinion Gauge #2.jpg

First Setting.jpg

Final Setting #1.jpg

Final Setting #2.jpg

Share this post


Link to post
Share on other sites

Hi Roger

I had my diff rebuilt by Jay at Crown Classics and it’s been perfect for the last 4000 miles. Very happy with all the work they have done.

Nigel

Share this post


Link to post
Share on other sites

Hi Ian,

              what dimensions do you work to with you pinion gauge.

On ed-h blog he used engineers parallel bars etc. He relates to another site where you have to rummage around to find the info so far I have failed.

I think I will have to use the suck it and see method.

 

Hi NIgel,

       he may well end up doing mine.

 

Roger

Share this post


Link to post
Share on other sites

Hi Roger,

It's the same pinion dimension as for a TR3a and its given in the workshop manual. It's measured from the ground thrust face of the back of the pinion (where the bearing abuts) to the centre line of the crown wheel bearings and for new CW&P it should be 3.4375" . I.e. To half a thou!

rgds Ian

Share this post


Link to post
Share on other sites

Hi Ian,

thanks for the dimensions  that may be worth knowing.

 

Only managed a couple of hours on the diff today.

I put 0.006" shim under the pinion rear big bearing cup and the pre-load feels good. It is over the 18in/lbs. but may well relax in service.

Sadly it feels as rough as old boots.  The bearing cup had some wear signs on it as if the rollers were digging in (not sure if that can happen)

So a new bearing tomorrow.

 

Having moved the pinion rearwards by 0.006" it has made no difference at all  to the crown wheel backlash.

So I shall investigate the shims in the carrier assembly 

 

Onwards and upwards.

 

Roger

Share this post


Link to post
Share on other sites

As Marcus has already said .006" is a heck of a lot. 

get yourself a tin of engineer blue (or yellow which I find easier to use) and check your contact pattern. Then you'll know which way to move each bit. 

Rgds Ian

Share this post


Link to post
Share on other sites

I put 0.006" shim under the pinion rear big bearing cup , ye say

this is moving pin deeper into mesh,  so will also need t,shuv a 6 thou shim under spacer

this why yer rollers feel ruff

 

pin shifting dont show up much on backlash, 6-7 thou = meb,e 1 thou difference

BUT,TT, 6 thou will show up ALOT,TT  on contact pattern , this ye dont say , did ye blue it !!!

 

movin CW aboot gives much moer differences

one effects the other

 

git sum blu onit, lots of it  :P:D

 

t,be honest, I cannae for the life of me see why there a clonk , even if diff is set wide.

a clonk can come frae the planets being loose{ shims too slack }

 

it can also come frae worn splines on flange an pin splines, but this will just show under load an on / off throttle

same as planet clonk

 

only other noise ive fun oot aboot is a clonk whenst a tooth or 2 or 3 is off

but this is a sort of nok,n click,n noise, no a clonk

 

markusbaffledikussed  at the moment:wacko:

 

 

Share this post


Link to post
Share on other sites
4 minutes ago, GT6M said:

I put 0.006" shim under the pinion rear big bearing cup , ye say

this is moving pin deeper into mesh,  so will also need t,shuv a 6 thou shim under spacer

this why yer rollers feel ruff

 

pin shifting dont show up much on backlash, 6-7 thou = meb,e 1 thou difference

BUT,TT, 6 thou will show up ALOT,TT  on contact pattern , this ye dont say , did ye blue it !!!

 

movin CW aboot gives much moer differences

one effects the other

 

git sum blu onit, lots of it  :P:D

 

t,be honest, I cannae for the life of me see why there a clonk , even if diff is set wide.

a clonk can come frae the planets being loose{ shims too slack }

 

it can also come frae worn splines on flange an pin splines, but this will just show under load an on / off throttle

same as planet clonk

 

only other noise ive fun oot aboot is a clonk whenst a tooth or 2 or 3 is off

but this is a sort of nok,n click,n noise, no a clonk

 

markusbaffledikussed  at the moment:wacko:

 

 

 

Happy to translate any of the above, John frae Cumbria.

John.

Share this post


Link to post
Share on other sites

Nneed t translaet foer me, I perfctly understand Markus:)

cheers,

Waldi

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.