Screeching tyres

Pat · Mar 30, 2008

Hello again,

A little strange this, but:
My P38 has taken to screeching tyres if i pull off in a rush (best not comment) and on sharp bends / round abouts. . .

A little concerned that it may be the diffs??
Oil has been changed recently.
Tyre pressures are correct.

I haven't had the tracking checked just yet.

Advice much appreciated.

locket · Mar 30, 2008

You could have a stuck viscous coupling. Do some slow turns and listen if you can hear the tyres grabbing or scrabbling.

slob · Mar 30, 2008

my mk1 escort used to do that

wills · Mar 31, 2008

Sounds like a seized viscous coupling. Jack one of the front wheels up. As it leaves the ground it should not turn at all. If it turns in either direction then you are winding the transmission up as you drive because the viscous coupling in the transfer box is seized.

-Wills

redrange · Mar 31, 2008

wills said:
Sounds like a seized viscous coupling. Jack one of the front wheels up. As it leaves the ground it should not turn at all. If it turns in either direction then you are winding the transmission up as you drive because the viscous coupling in the transfer box is seized.

-Wills

i was under the impression it SHOULD turn! if it dont then you have a siezed coupling, if it spins freely then the coupling is broken, it should in be in N and with a breaker bar on a wheel nut you should be just able to move it but slowly! very slowly and with a constant effort!

wills · Mar 31, 2008

redrange said:
i was under the impression it SHOULD turn! if it dont then you have a siezed coupling, if it spins freely then the coupling is broken, it should in be in N and with a breaker bar on a wheel nut you should be just able to move it but slowly! very slowly and with a constant effort!

It should turn. Read what I put again, it shouldn't turn as it LEAVES the ground, it should stay perfectly still. Only then, once its free from the ground you should be able to do this...

-Wills

Pat · Mar 31, 2008

So - if the viscous coupling is shot, I should not be able to turn the wheel once off the ground?
Or am I being needlessly thick?

How nasty is the viscous coupling replacement on a manual P38 DSE?
& how expensive are they???

wills · Mar 31, 2008

Pat said:
So - if the viscous coupling is shot, I should not be able to turn the wheel once off the ground?
Or am I being needlessly thick?

How nasty is the viscous coupling replacement on a manual P38 DSE?
& how expensive are they???

Correct, you wont be able to turn the wheel by hand if its seized.

I dont know how easy it is to replace though. When I replaced my gearbox I also replaced my transfer box at the same time, both parts were recons and the new transfer box came with a new VC.

Before I replaced these you couldnt turn the front wheel as shown in the video above.

Hopefully someone who has replaced their viscous coupling will come along and help out with some details soon. However, how many miles has the transfer box covered, if you are replacing the viscous coupling it might be worth doing the transfer chain at the same time, in for a penny, in for a pound and all that.

-Wills

Pat · Mar 31, 2008

Cheers Wills
Ah, mileage. . .
That would be just a little on the high side.
Only about 180,000 miles.
Not that high really – who am i kidding

v8kenny · Mar 31, 2008

Viscous coupling is fairly easy to do
No need to take the transfer box out - just the cover after you have dropped the front prop
Rave gives a reasonable enough explanation in the transfer box repair section
As for cost, I don't know - a classic VC can be had for between £150 - £350 so definitely shop around !

Pat · Apr 4, 2008

Well, had a go at turning one lifted wheel by hand - not really managed it.
Before anybody comments - it was out of gear and the handbrake was off.
It appears to have excessive wear on the inside edge of the front wheels - so possibly tracking too. . .

mickobrien · Apr 5, 2008

this sounds silly BUT have you had new tyres resently? and are they directional... my old bmw had new tyres fitted and the muppets had fitted the tyres on wrong, made this noise, took it back and they swapped them round. cured it..
Just a thought.im proberly way of the mark!

Pat · Apr 5, 2008

Good call, but alas no, they've been there for the last +30k miles and still have some life in them yet. They're not directional and its been six months since I rotated them. . .
think I'll start with rotating them and having the tracking done.
Then. . .
Can anybody suggest a supplier of a viscous coupling?
(That won't want an arm & a leg - have grown attached to them)

Is the viscous coupling the same in all the RR's?
What about one from a low miler from a breaker?

lanmjdun · Apr 5, 2008

Ashcroft Transmissions for a start, hunt around the adverts in LRO magazine as Paddocks/Craddocks/MM4x4 sometimes have deals on them. They are approx £250. Have a suspicion that P38 and Classics share the same unit, but they are usually not listed as interchangeable, same price anyway.

Breaker might be an option, if you could get someone to split a transfer box which is unlikely, and even then how good is that one?

Another way to condemn a viscous coupling is go to your nearest Tesco car park (Sainsbury's or Asda will do also), put full lock on and take your foot of the accelerator. The vehicle should keep moving in a tight (for a RR) circle. If it slows and requires some gas then its a sign the transmission is trying to wind up and you need more power to spin the tyres and free it - therefore your vc is seized or near to. That works for auto, don't know about manual, I guess it would kangaroo then stall.

Pat · Apr 6, 2008

As per suggestions, tried putting it to full lock and going around in circles (both directions), no tyre scrabbling, no nasty knocks or big bangs. It seems to cough a little, then off it goes. . .
Tracking and tyre rotation it is then.

If not, then, its off to a friendly LR specialist

Screeching tyres

Pat

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locket

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slob

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wills

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redrange

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wills

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Pat

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wills

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Pat

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v8kenny

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Pat

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mickobrien

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Pat

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lanmjdun

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Pat

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