Advice needed from a proper mechanic

[AndyStobbs]

Pm your reg. if you like. I will ask my motor factors tomorrow - Im ordering daily so its no hardship - they will be happy to check.

Also it may have a harmonic balancer in the engine. This could literally be a special front pulley designed to soak up the vibes. Recently changed one on a 320d BMW. Getting quite common now. I havnt worked on a great many toyotas lately so a bit out of touch with where they upto as regards parts they're fitting.

 

[the repair man]

I'm starting to wish I hadn't bought cheapo disks now, the idea of a heavy unbalanced mass on the end of the drive shaft is about as good a way as I can describe what it feels like.
However, the very slight play where the shaft enters the gearbox/diff also concerns me, although everything I've read suggests that it is normal.

 

[the repair man]

Yeah I had a porsche with balance shafts, this does have a pulley on a stub shaft on the back of the block that doesn't seem to drive anything. But it is definitely manifesting itself in the n/s/f wheel or shaft, whether or not it is starting there I don't know.
Pm'd you the reg.
Cheers for your efforts, greatly appreciated.

 

[AndyStobbs]

Take the discs and wheels off if its troubling you and run it on the axle stands again.
I fit cheapish discs all day long to the majority of cars I see. Never had an issue yet. What vrand were they, do you remember? Pretty difficult to make an unbalanced disc, I would'e thought.

 

[the repair man]

No idea! About £70 off ebay lol It doesn't concern me, its just when you mentioned them, that seemed like it would give the same symptoms as I'm getting. Also neither garage even mentioned them, it went straight from wheel balancing to change the drive shaft, then when that didn't fix it, they said change the other then! So I went to a different garage, and they fitted the other side, when that made no difference 3 of the mechs there took the car for a drive. In the end, the boss said he would go for a new gearbox. Being an arrogant engineer, I decided he was wrong, and besides, I can't afford a new gearbox!

 

[AndyStobbs]

Ah I have no experience of ebay parts so can't really comment on the quality you might find there.
They sound as if they might have bypassed a few steps but it can be difficult sometimes to narrow things down. Its the load angle that is perplexing me most. An unbalanced weight is an unbalanced weight regardless of engine load. Im tending to think more powertrain than drivetrain issue - but thats only a guesstimation over the internet.

 

[wookie]

I'm starting to wish I hadn't bought cheapo disks now, the idea of a heavy unbalanced mass on the end of the drive shaft is about as good a way as I can describe what it feels like.

Why don't you swop the discs over, if the problem swops sides you've found it if not you can eliminate the discs as the problem.

Is the vibration the same at say 50mph in forth gear & same speed in fifth gear ? that should tell you if it's revs or speed dependant.

hth

 

[the repair man]

The load angle? I think I understand, but then an unbalanced wheel might be fine for the majority of motoring, but awful between say 50-65mph. If I understand you right, surely that is the same thing? I don't suppose it is engine load as such, in that there is more load under hard acceleration in 2nd than gentle acceleration in 4th, it is just this is when it becomes bad. However, if I change gear say 4th to 5th or 6th, and try to accelerate at the same rate, the vibration remains, regardless of the gear. So the road speed is relevant.

 

[blenkie1]

Did you get the wheels balanced off the car or on it? Not sure if any firms still do it but you used to be able to get the wheels balanced on the car. You sat on a little machine which spun the tyre so I would think would be effectivley balancing everything not just the tyre. The only problem with it was that you had put the wheel back on the same studs it came off. Personally it sounds gearbox related but sounds and knocks can be deceptive on cars. I take it is a straight car not been crashed or anything?

 

[AndyStobbs]

But aren't you saying that you could be cruising at 50 (for the sake of argument) and the vibration isn't too bad on the flat. Then comes a hill and you want to maintain 50, so you press the pedal further and the vibration worsens but your road speed and revs and gear are all constant still?

 

[the repair man]

Why don't you swop the discs over, if the problem swops sides you've found it if not you can eliminate the discs as the problem.

Is the vibration the same at say 50mph in forth gear & same speed in fifth gear ? that should tell you if it's revs or speed dependant.

hth

Gear makes no difference really, all the higher gears ( which in turn means lower rpm ) from 40 or 50 mph exhibit the bad vibration. I think say 2nd at 50 mph wouldn't do it, but then I may just not have noticed as I would have been accelerating through 50, not sitting at that speed.
Good idea re swapping the disks over, so simple yet I didn't think of it doh!
It may help, although the problem existed before I changed the disks and drive shafts, I spoke to someone had an engine mount go on one of these cars, so will inspect that again tomorrow. He said the mount was fine, but when removed the bolt going into the chassis had threaded and wasn't holding anything.

 

[dannyp]

shouting DMF to me

 

[normspanners]

firstly swap wheels front to rear and test, when you said that you ran it up to 150 mph but with only one wheel turning, well because of the diff that wheel was doing 300mph !! it sounds to me that the diff planet gear cross shaft bearings are worn. I cannot see it being a disc they would not be load critical, only under braking.
the way to load test the shafts and diff, is to put the car on stands, under the wishbones so as to keep it at normal running height you may have to lift the rear on wood to save the weight transfer to the rear.
Then put your foot on the brakes and clamp the brake hose with a hose clamp which then locks that wheel, the one with the clamp, take you foot off the brakes start the car, then run the car in gear but remember to half the indicated speed, you can then GENTLY apply the brake again, that allows you to vary the load on that wheel but also then loads the diff and shaft on the none clamped side you may have to switch off your traction control, if fitted, to allow you to get any speed and you may also have to pull the abs fuse to stop that kicking in, do both wheels and you should have a marked difference if it is one side or the other, you can lay under the car and observe what is happening if it is the same it would suggest the diff gears/ bearings. you cannot always hear diff bearings as a noise they just allow the whole diff to jump around in its housing.
old escorts FWD used to distroy their diff brgs the only thing you knew was the speedo stopped working because the diff had move that much, the speedo gear had moved out of mesh.

 

[the repair man]

Yes I knew about clamping the brake lines, I may try that tomorrow also. However, regardless how slow or fast I had the wheels spinning, there was no movement I could see.
It does please me I can now say I've had it up to 300mph!
DMF ?? Whats that then. On the note of pulling abs fuse, there is another niggle, which I assumed was unconnected. The traction control alarm sounds when on the gentle corners, dry day etc. I assumed this was a sensor niggle, so I just turned it off. Perhaps it is connected to the problem. Do they work soley off the abs reluctor, or is there pitch and yaw sensors or other sneaky sensors?

 

[normspanners]

sorry I was editing my last message please re read.
DMF is a flywheel that is what it says dual mass ie in two pieces but one piece is damped they are expensive CRAP the biggest money spinners for car manufacturers for years some you can ONLY get from the main sealers and they can be up to £1000 !!!! I doubt it will be the DMF they usually rattle, but at engine speed.

 

[normspanners]

Ah ABS some traction control ecus actually apply the brake to the spinning wheel I had a volvo 4x4 that was putting the brake on at 30- 40 mph that was down to a cracked abs reluctor ring

 

[AndyStobbs]

Preliminary enquiry suggests solid flywheel anyway. If your car has ESP there will be longtitudinal, lateral and yaw sensors also a steering angle sensor. If its just TC then only the standard ABS reluctors are required.

 

[the repair man]

I see, so all I need is a week, a rolling road, a car lift, £1k spare, reinforced knuckles and a lot of patience...hmm I have a socket set! I think new drive shafts for this car are over £1000, unless of course your a US citizen, then about £100! Oh well, tomorrow, its jack car up, one side at a time, lock other wheel, run it up to 50mph, see what I can see again. Then swap disks over to opposite sides, test again. Although it doesnt seem to do it on jacks or with no real load. Then, I'm gunno rip n/s driveshaft out ( again ) and see if any play in the diff. I have a full spare drive shaft here, that the half shaft fits both sides, so may find a use for that. Then, if I'm still sane, the car may catch fire before my insurance runs out!

 

[the repair man]

umm not sure Andy, it does try to brake the wheels sometimes, under what I consider normal, or slightly hasty driving, but certainly not really pushing it. I will check the book, see if its esp..These cars have an electronic power steering system, I don't suppose that could cause this kind of fault?

 

[AndyStobbs]

I see, so all I need is a week, a rolling road, a car lift, £1k spare, reinforced knuckles and a lot of patience...

Yup and thats just for a service now days. If you actually want to fix cars you need thousands of pounds of computers too. Oh well haha, it could be worse.