Montego diesel torque steer problem?

[AFRICAR]

For the last 5 years I have had 2 Montego diesel estates. I have tuned the engines to pull so there is no flat spot at low revs, they pull like a trains.

I have a problem I do not know how to cure which seems to be a steering problem, when the turbo kicks in the car lurches to the right and when backing off, it pulls to the left.

The steering has been checked out, it passed with flying colours.
Since then I have so far replaced both the bottom swivels, both struts, both wishbones, all that is left to change is the rack, but nothing has cured the problem.

All my test runs have been on the same road, at 30-40 but the weir thing is when the I put the car in neutral at 30-40mph the car is running perfectly well, straight and true, no steering problems at all. In other words the problem is only happening when under power.

Do anyone have any ideas how to cure this? The car has 88,000 on the clock.

[E_T_V]

Ball joints on the rack (either inner or outer ones), would be my first guess.

Some torque steer is inevitable I'm afraid, you just get used to it.

[G Force]

Hi & welcome to the forums. Like ETV says a certain amount of natural torque steer is unavoidable but there are ways to tackle unnatural torque steer.

It is important to make sure that there is no wear or play in the steering and suspension components & the steering geometry is spot on. You can set the front wheel alignment to the max toe out tolerance to help combat the N/S wheel toeing in under acceleration. Make sure the front wishbone bush is not moving in the sub frame, it is possible even with the bolt correctly torqued the bush is not clamped securely due to manufacturing tolerances. It often requires a certain amount of overtorqueing of the bolt to ensure the sub frame deflects enough to clamp the bush. Changing the wishbone bushes to a more solid type may help, such as powerflex bushes.

Gary

[Guest]

As the others have said torque steer will happen, is due to the fact that the driveshafts are of an unequal lenght, so when under power/torque power comes out of the gearbox and the power can get to the lefthand wheel quicker causing it to spin up and the car will dive to that side and then back to the right as the power reaches the right hand wheel. Torque steer is increased in the wet and could cause the car to dive to the right if the righthand wheel has more grip or vise verser.

Turbo engined cars are worset for it as the torque and power increases suddenly when the turbo kicks in. Rover did go some way to curing the problem by fitting a torsen diff to all their cars fitted with the T series turbo engine, and computer controlling the turbo waste gate to limit the torque at about 240nm.

I fitted the torsen diff gearbox to my old maestro turbo and it worked quite well, though took more time to get the speedo to read right afterwards.

[G Force]

As the others have said torque steer will happen, is due to the fact that the driveshafts are of an unequal lenght, so when under power/torque power comes out of the gearbox and the power can get to the lefthand wheel quicker causing it to spin up and the car will dive to that side and then back to the right as the power reaches the right hand wheel.

Its not really that the n/s wheel gets the power earlier that causes the torque steer. Natural Torque steer is mainly due to the shorter drive shaft being more rigid and resistant to twisting than the longer drive shaft, this results in more torque being applied through the shorter drive shaft. When the throttle is closed the car straightens up due to the steering geometry (castor angle) giving the effect of steering rapidly in the opposite direction.

Gary

[AFRICAR]

torque steer

many thanks for the replies.

natural torque, if only, we are talking Montego diesel here. Having said that I personally know the guy who tuned up a Maestro engine and got 403bhp out of it on the dyno. you may have seen the car race around Thurston.

I have driven and repaired Montegos for the last 10 years, and I have never come across this one before. I going to replace the gearbox because this is only thing left that is not new. I think it is the diff locking itself up somehow.

If this does not cure the problem, I shall break it up for spares for my other Montego.
I'm looking for a right brake calliper, after 100,000 miles they wear and cause massive vibration when braking hard.

keep smiling

Africar

[E_T_V]

A quick check on the gearbox is to try to lift the inner CV joints up and down. There will be a little movement (that is normal), however lots indicates worn diff bearings (usually through lack of oil). If this is the case then you can either swap the box for another or fit a new set of diff bearings to it (simple enough to do). The wear has to be pretty bad in order to notice it as torque steer though. Another thing to check is the engine mounts. The lower gearbox mount frequently tried to undo itself, and the offside engine mount can give problems/breakup.

[AFRICAR]

update of steering torque problem could be back axle

Hello everyone

Just letting you know that after changing to a higher ratio gearbox, the torque
steer is still the same, i.e. nothing has improved, thereby the diff was ok. The estate is still wondering across the road.


Someone suggested looking at the back axle. Both swing arm bushes are moving a lot when forced to move with a crowbar, i.e. could this problem be rear wheel steer? not torque steer.

I'm going to try changing the rear bushes next.

all the best
Africar

[AFRICAR]

Hello Everyone

It has been a very long time since I said anything about the above steering torque problem.
The problem was the front lower wishbone bushes.
Of course I only found this out, only after replacing every other suspension bush on the car.
The rubber bush cracked up inside the bush, therefore the putting a crowbar on the wishbone did not show any movement.
There are not many bushes left to purchase, so I bought enough to put some in stock, just in case it happens again.

The side issue was, it cost me £6000 because my wife refused to drive the Montego any more because it was uncontrollable.
The £6000 was for a Passat estate. The replacement bushes cost me about £5 but I was a bit late finding out the problem.

Power steering rack rubber gaiters. = part no SRB085 or 7E010-4 Some are still available but stocks are getting short, likewise the bottom steering swivels.

I'm still managing to get my Montego estate through the mot but parts are getting to be a problem.

I hope the above info helps someone else.

all the best

Africar