2.5TC diff

[Mikeo632]

Hi all.

My recently aquired 2.5TC Estate is a solid but scruffy example in need of TLC.

The most urgent problem involves a vibration coming in at about 55mph. Had hoped it was the prop UJ's, but those plus the UJ's on the drive shafts have a very small amount of movement, but nothing I would think of as worrying. There is also a small amount of rotational movement on the driveshaft mid-joints, but again, not a great deal. What there is, is a leak from the diff, & after scraping years worth of crud/oil from the diff & surrounding area, & cleaning with degreaser (how I love that job), it appears to be coming from the nose of the diff.

What I think there also might be, is play in the diff. With the car in the air, handbrake on, I can rotate the prop back & forwards with no movement of the driveshafts . Measuring the movement from one of the nuts on the prop flange, I have movement of 7-8mm (Backlash?)

Is that normal, or does this seem excessive, & therefore, would it possibly lead to the vibration?

Would appreciate thoughts.

Mike.

[Pete Lewis]

any float on a UJ is unhelpfull when chasing vibrations

i would say the quill shaft bearing is failing especially if oil is leaking gives a mid range vibration ,live mirror etc.

is a single row ball race with a integral seal , the seal in the diff is in diff case not the quill extention tube

there are two qualities of oil seal  plastic  or leather  see chris witors site

as an estate you should have a removable rear support on the back of the diff if you drop the shafts and remove this the diff will come out 

rearward without the frightening myths of having to remove the whole rear suspension assy'  the quill shaft bearing is held by simple circlip

and can be tapped out leaving the quill tube in place .   hard on a mk saloon as the rear end is not detachable but  sure mk1  and stag and estates have the rear support detachable,  makes it quite easy , still heavy.

what you have in backlash is play on the planet and sungears   not to worry thats normal 

if output seals are leaking it took a 20t press to get the flanges off the shafts ,  nightmare !!

hence why many supply as   exchange ??

 

 

 

 

[poppyman]

3 hours ago, Mikeo632 said:

Hi all.

My recently aquired 2.5TC Estate is a solid but scruffy example in need of TLC.

The most urgent problem involves a vibration coming in at about 55mph.

Can you drive out of the vibration Mike? If so i would suggest getting the wheels balanced as that is the speed wheel vibes tend to start at for some reason. Sometimes increase in speed makes it worse or more often it will disapear.

Tony.

[thescrapman]

I have changed the diff seal on a couple of cars leaving the nose extension in place, they have started leaking again soon afterwards.

i think it is down to the wiggling trying to get the diff back in place damages the seal.

it only takes an extra 5 mins to take the whole diff Assembly out with the extension attached and that way it can be more easily worked on and the extension can be carefully fitted on the bench.

[Pete Lewis]

so how did the quill extention come out of the sub frame its locked in by the frame flanges  which is where the idea of dropping the whole frame comes from   

when you have the removable rear support its a straight on  off,,  on all except  on a mk2   saloon with the wheel well and cast fixed rear end 

done that on mine its yes a bit of a  fight . always use the leather seal its more compliant to misjudged alignments 

pete

[Mikeo632]

Thanks all for the speedy replies.

Following your advice, & starting from the basics, I checked the tyre pressures again, having checked them before setting off from the vendors. The vendors TP guage read mid 20's all round which was ok. Having now checked at home, the TP's were all 10psi down! Correcting that has made a hell of a difference, it now seems happier at 70 than 55. There is still a vibration, but much less so, therefore am having all wheels rebalanced Saturday morning.

I still have some doubts that balancing will totally cure, it might be my imagination, but now the TP's are correct, the remaining vibration could be dependent on engine revs. Ie 4th at 60 there is a certain tempo of vibration, engage OD & the tempo reduces? But if I am right in that, it would point to engine rather than diff?

Did I imagine it, or did I read somewhere about a vibration damper on the front pulley of the crank?

Mike.

[Pete Lewis]

There is a damper on the front crank pulley but thats for harmonics in the crank  its unlikely to make engine vibration that shakes the car

Does the mirror vibrate ???

Theres a post on here about alternator makes a vibration problem

 Theres a wealth of difference between wheel wobble and prop rotation speeds like the prop  does x4 the wheel rpm so vibration frequencies are wildly different 

And historically quill shaft problems  are very frequent 

Pete

 

 

[JohnD]

A vibration coming frorm the engine would happen at several road speeds but the same engine speed, which is not what you describe.

If it happens at a cetain road speed, then yes, tyres/wheels, halfshafts or propshaft.    Diff unlikely IMHO.

The prop is most likely, as it's wider than the halfshafts.     They were balanced in the factory and small steel plates tack welded on to balance.  They are vulnerable to corrosion/road damage, and if lost the prop goes out of balance.     Corrosion adds to the weight, unevenely and might do the same.

Clean the prop, look for the balance weight, or its absence.

JOhn

 

[Mikeo632]

Pete.

If I am looking at the Quill shaft bearing, if I disconnect the prop, would there be play in the quill shaft with it in place that would indicate bearing wear, or would I need to take it apart to investigate?

Thanks.

Mike.

[Pete Lewis]

its just a  one off  single row ball race  , detecting any float is unlikely,  my removed  quill bearing runs well but thats all we changed apart from the pinion oil seal  and the mirror shake has  ..........disappeared.   ( used a CW rhp bearing not a cheapie) 

drive shaft ujs are easy to change as removing the drive shafts is easy. a good clean and re grease the shaft telescopes is worthwhile

fitting poly bushes to the trailing arms lined up the toe in and reduced the tail twitch coming off a round about is very rare now.

so detecting and quill problem is not likely , its supported by the splined drive hub on the pinion and the single race 

so doesnt take much to upset it in the wear and tear of life 

Pete

 

[thescrapman]

On 21/10/2019 at 09:28, Pete Lewis said:

so how did the quill extention come out of the sub frame its locked in by the frame flanges  which is where the idea of dropping the whole frame comes from   

when you have the removable rear support its a straight on  off,,  on all except  on a mk2   saloon with the wheel well and cast fixed rear end 

done that on mine its yes a bit of a  fight . always use the leather seal its more compliant to misjudged alignments 

pete

Take the wheels off, undo the 3 flanges, and thenthe 4 long bolts.undo the rear mount nuts.

lever the 2 subframes down and the extension will drop out.

 

to refit push one side in first and then lever subframes down and push diff into place

[poppyman]

We found a rear end noise on a Stag recently that turned out to be the quill shaft brg. The noise was unbelivable, sounded like a wheel brg. But after disconnecting the drive shafts one at a time and even disconnecting the prop at the gearbox to rule that out... it was that little sod, no play at all and no noise in reverse..... As the car was a daily driver we just fitted a second hand quill shaft complete with an old brg.... It's been fine ever since. A lot easier on a Stag though.

Tony

[Pete Lewis]

make you wonder why on the MK2 they dropped the demountable support  and added a fixed   figging heavy cast back end

I like my MK2 but its got the hunk diff and two blasted SU    ....why did i buy this one  ... HYA  its called Hi Ya or Hyacinth   dont ask 

Pete

[Mikeo632]

Ok, so have had all wheels balanced, & after a quick drive, the difference is significant! Much smoother, no nasty vibrations at low speed, will check at a higher speed once I have sorted the brake servo!

Mike.

[Mikeo632]

Hi again.

Have now dropped the diff (seperate to extension), removed the extension & replaced the quill bearing.

Both driveshaft output flanges appear to have slight leaks, although to be fair, there was so much crud covering the underside of the diff, it could be a real small weep over many many years! But, having got it apart, seems sensible to try to resolve, so have new oilseals from Rimmers. Will try to find somewhere with a press to remove the flanges tomorrow! Have also got a replacement pinion oil seal (Part No 137346) from Rimmers, as oil seemed to be collecting around the quill shaft extension front flange, meaning it was possible that the leak was coming from the front (pinion shaft) oil seal? Possibly supported by the quantity of oil that came out when I seperated the diff from the extension??

According to Rimmers, the part number is correct, however, when I compare the new seal to the current set up in place, it appears too big a diameter. (See pics). The old seal appears to fit inside the metal ring with the number stamped on it, the diameter of the new seal would seem to match the outer of the metal ring with the number stamped on it?

Anyone any experience of this? If fitting the new seal means I have to dismantle the diff, then I think I will leave well alone.

Mike.

[Pete Lewis]

it takes a heck of a load to spilt the short shaft coupling off over 12tons on mine 

cant say about the seal i used a leather one from chris witor  so far so good

Pete

[Nick Jones]

The metal ring is part of the casing. The seal needs to fit inside it.

As Pete notes, the flanges on the side shafts are damn tight. My 10 tonne press failed, the work one succeeded at 14 tonnes and a whopping 18 tonnes. That was a BIG bang!

Yes, you should definitely worry about the quill shaft bearing. It’s a sealed headed bearing but Leaking oil washes the grease out and when the flow of oil is stemmed by a new seal, it dries out and dies.

You could renew it but note that most of the usual suspects sell some nasty modern equivalent rather than the original RHP one and these don’t last long. If your existing bearing is still smooth running you can carefully knock it out (don’t hammer across the race), pick out the oil seals, give it a rinse out and repack with bearing grease before refitting the seals. That what I did when my new bearing starting howling after less than 2000 miles. Had to rescue the old bearing from the bin first!

Nick

[Mikeo632]

Have replaced the quill shaft bearing with a replacement from Rimmers. There was a reasonable amount of oil that came out of the quill shaft extension when I (a) seprated the diff from the extension when lowering the diff, & (b) when I removed the extension from the car.

Is the diff oil supposed to go into the extension or does this mean the front (pinnion?) oilseal on the diff has failed?

If so, how do I replace the oil seal? Does the oilseal currently in place just pull out of the casing? As mentioned, the one suppled by Rimmers appears to be of a larger diameter then the one fitted, but is the right part according to Rimmers website.

[Mikeo632]

Sorry Nick, just re-read your post.

So, the new bearing should be ok, but I need to replace the oilseal, & it would seem that the one supplied by Rimmers is incorrect as it will not fit within the metal ring?

Will order the leather one from CW which should hopefully fit ok. Will talk to Rimmers re the one supplied.

[thescrapman]

Quill shaft extension should be dry. All oil needs to be in the diff, no where else.

 

the metal rang with the number needs to come out I am absolutely sure

[Pete Lewis]

big agree  the whole metal surround has to be hooked out 

mine was a hack it to death to get it to break loose 

if you need a RHP quill brg  its avail from CW

pete

[Nick Jones]

1 hour ago, Mikeo632 said:

Have replaced the quill shaft bearing with a replacement from Rimmers.

Yeah..... the one that lasted 2k came from there.  If the one that came out is RHP and runs smooth - hang on to it!

Agree that the ring with the number on it needs to come out but the ring outside that is part of the casing.

Nick

[Mikeo632]

Thanks all. Will wait for the leather seal to arrive from CW before hacking out the metal ring & replacing the seal. Flanges currently with a friendly engineering firm.

Mike.