P38A 2001 Diesel Running with no frt propshaft
- Thread starter vtwin
- Start date
This site contains affiliate links for which LandyZone may be compensated if you make a purchase.
myfirstl322
Well-Known Member
- Posts
- 41,354
- Location
- Hoots mon...
RWD sounds just dandy.
Can't see it hurting, and it might be fun.
Can't see it hurting, and it might be fun.
kds
Well-Known Member
- Posts
- 2,262
- Location
- old,ugly, tired in Lincoln.
They just dont go round corners the same with no front prop.
Thks point taken on handling it will be interesting to see how it goes, I do have the last P38 for spares but it will take a bit of time to get it out and double check the CVU is ok before swapping it over, Ashcroft still do them but at roughly £300 plus costs its worth me checking the spare one first. I am not sure how long it had been seized but its taken the edge of front tyres fitted this year, I also changed the auto trans filter and oil which was bad, not sure if the CVU was the cause but probably not helping, while I was at it I removed the driving spot lamp that blocks off the auto trans cooler, I know it has an electric fan but as I never use the driving lamp it can only help.
- Posts
- 19,297
- Location
- Buckinghamshire, UK. ('95 DT)
Edges of the tyres could be a lot of things other than the VCU. Bushes could be worn or steering out of alignment. The list goes on.
Agreed, I had given it a good check over thinking it was bushes etc. and tracking had been checked twice recently when I first spotted the tyre wear, put them on the back now and will keep a good check on the fronts now, CVU definitely seized long bar on a wheel nut and another pulling as hard as we could on the wheel, both sides checked just in case.
Not sure about your test there. It should be jack up the front. Bar on wheel nut. Wheel and prop should turn slowly. TBH I think the test is a bit simplistic. This weather try driving on a slippy surface. One wheel should spin a bit before the VC locks and engages the other wheels. It's better if you watch someone else drive! The more seized the more it's all four spin simultaneously at the same time. Ironically the better it is off road! (Diffs locked)
That is my understanding but never having tested a new vs a seized it's a bit of a guess. The fluid must be close to locking to work as an effective 4wd centre diff though.
That is my understanding but never having tested a new vs a seized it's a bit of a guess. The fluid must be close to locking to work as an effective 4wd centre diff though.
jamesmartin
Well-Known Member
- Posts
- 91,879
- Location
- louth lincs
jack up one front wheel and g/box in any apart from p, its very accurate if wheel dont turn vc is locked, those vcs have a limited life
Orangebean
Active Member
- Posts
- 137
- Location
- South Hams, Devon
The definitve test (courtesy of Ashcrofts) for VC. Ambient temperature might be an issue:
RRC, Workshop Manual, Section 41 Transfer Gearbox, Overhaul, Dismantle, Inspection & Overhaul.
You can either do this test on the bench or in the car with the handbrake on and one front wheel lifted.
Viscous unit - rolling resistance Bench check NOTE: Testing should be carried out in an ambient of 20 deg C.
1) Secure the output shaft ...
2) Apply a clockwise torque of 27 Nm to the (front propshaft) output flange nut. If no resistance to turn is felt, unit requires replacing.
3) If resistance to turn is felt, apply a clockwise torque of 20Nm to the (front propshaft) output flange nut for 1 minute, this should result in a rotation of approximately 25 deg - 30 deg. If no rotation or a greater force is required, unit requires replacing.
27 Nm = 20 lbf-ft 20 Nm = 15 lbf-ft
RRC, Workshop Manual, Section 41 Transfer Gearbox, Overhaul, Dismantle, Inspection & Overhaul.
You can either do this test on the bench or in the car with the handbrake on and one front wheel lifted.
Viscous unit - rolling resistance Bench check NOTE: Testing should be carried out in an ambient of 20 deg C.
1) Secure the output shaft ...
2) Apply a clockwise torque of 27 Nm to the (front propshaft) output flange nut. If no resistance to turn is felt, unit requires replacing.
3) If resistance to turn is felt, apply a clockwise torque of 20Nm to the (front propshaft) output flange nut for 1 minute, this should result in a rotation of approximately 25 deg - 30 deg. If no rotation or a greater force is required, unit requires replacing.
27 Nm = 20 lbf-ft 20 Nm = 15 lbf-ft
Quite a few miles now with no front prop, it does not have the previous steering issues similar to tracking faults any more, front tyre wear seems normal as well and as a bonus fuel consumption is better. On the down side fast cornering is not as good and in the snow and ice it felt like it was going to slide away at anytime on corners. As soon as possible I will change the VC and get the front prop back on as no point in having one that gets stuck in a gateway!
- Posts
- 19,297
- Location
- Buckinghamshire, UK. ('95 DT)
Do they do it in exchange for the old one? How much?
Orangebean
Active Member
- Posts
- 137
- Location
- South Hams, Devon
Exchange- out of stock at the moment. £295 + vat +deposit + delivery
http://www.ashcroft-transmissions.co.uk/viscous-couplings/range-rover-viscous-coupling.html
- Posts
- 19,297
- Location
- Buckinghamshire, UK. ('95 DT)
I'm theorising here but it occurs to me the VCU locks up from heat. I'm thinking with the car standing still the VCU might still be free using that test but as it starts to die the heat generated by normal driving might be enough to partially lock it and cause the tyre wear he observed. Guess we'll find out shortly how long his tyres last!
- Posts
- 19,297
- Location
- Buckinghamshire, UK. ('95 DT)
That's pretty reasonable, I think. Bit worried by the press unit out part. Press of some sort required?
How to fit a viscous coupling unit
1) Remove front prop shaft
2) Drain oil from transfer box
3) Support gearbox and remove right hand gearbox mount
4) Remove bolt holding Viscous Coupling housing to transfer box
5) Rotate, to break silicone, and remove Viscous Coupling housing
6) Remove flange nut and flange and press out Viscous Coupling
7) Clean all joint faces
8) Replace Viscous Coupling and reassemble in reverse order
jamesmartin
Well-Known Member
- Posts
- 91,879
- Location
- louth lincs
no, test works , we tested hundreds of vcs off the vehicle
- Posts
- 19,297
- Location
- Buckinghamshire, UK. ('95 DT)
Off vehicle? So that's direct to the output shaft? I was talking of the one where you lift a wheel and try to turn. That's a lot harder to guage the force.
I note Ashcrofts reckon the units last about a 100k miles (well, I guess they would
). Mine's at 150k and never been replaced as far as I know!
Orangebean
Active Member
- Posts
- 137
- Location
- South Hams, Devon
Doesn't lock from heat. The silicone filling is a non-Newtonian fluid that resists the torque effect. Think torque converter but filled with silicone. The harder/ faster the torque is applied, the more the silicone resists, so a small or no difference between the 2 sides allows the silicone to behave like a liquid (VCU unlocked). When there's a difference between the two sides, the silicone stiffens and, in effect moves toward locking the two sides together.
When the silicone craps out from old age and thickens the VCU becomes, in effect, locked.
jamesmartin
Well-Known Member
- Posts
- 91,879
- Location
- louth lincs
the principle is the same ,ive tested many that way, 100k is what was thought average lifespan though there are a lot of variables to life span when we were reconditioning borg warners for lr in the 1990sOff vehicle? So that's direct to the output shaft? I was talking of the one where you lift a wheel and try to turn. That's a lot harder to guage the force.
I note Ashcrofts reckon the units last about a 100k miles (well, I guess they would
- Posts
- 19,297
- Location
- Buckinghamshire, UK. ('95 DT)
Ah, OK. I thought I'd read somewhere it was the heat. Non-Newtonian fluid makes sense.
Well mine gets to play on slippy stuff so gets a good workout. I regularly have the traction control lights flickering although that is across the axle rather than axles.
Well mine gets to play on slippy stuff so gets a good workout. I regularly have the traction control lights flickering although that is across the axle rather than axles.
