just fitted one piece prop and new gearbox mount on my uk manual car hasn't made the slightest difference still get vibes altough i am testing on axle stands ( shouldnt make any difference plus wheels are off) right any brain boxes out there have any ideas

1 could it be rear diff ?

2 should i go back to 2 piece prop?

3 dont say rebalance prop it has been done twice

4 burn car?

i will give lots of money to anyone that comes up with solution

cheers mark

A: bushes

B: Gearbox?

C: Wheel balancing

D: Are all your tyres fine?

 

Just have to go through the basics.

Are you sure you have no chassis damage?

But go check the small things first.

process of elimination

when you say bushes which bushes and when you say gearbox how would i check that with the prop off i can spin the car up to 60mph and it is smooth

Timmy found a post on carsurvey which showed http://www.carsurvey.org/review_3859.html

 

I did my best to write this up on http://www.netcomuk.co.uk/~webster/propvibesintro.htm

 

It seems there is not one main problem - just a mix of everything to do with things that rotate. Not helpful - sorry

 

Hadn't spotted in your post about the centre bearing? Have you done this yet? I know of two people who said this made a difference, my bloke said mine wasn't right so I guess when the exhaust comes off to put the Mongoose on, we'll belt the centre bearing with something heavy.

 

BTW do check what Spinning said about one piece props - I didn't know that!

Here`s a thought make sure you have not got a misfire or rough running in the rev/speed range where the vibration is worse, do this by knocking the car in to neutral and see if vibs are the same or stop,just a thought and if anything it is something else eliminated.

 

Jeff TT

Mark A. Have you inspected your driveshafts/halfshafts yet??? My Mrs had her front wheel bearing renewed in her old 405, dumb mechanic reassembled driveshaft incorrectly. Drove it 1/4 mile and the thing shook itself to bits!!!! Returned it to him and he fitted a new driveshaft (which was broke) and it was perfect again!

 

So my advice to you is check your driveshafts. By the way, do you get vibes with clutch down? I.E. engine vibes?? Or is it 100% transmission??

 

Regards

 

Robert

Just read your post properly. On your axle stands, select 2nd or 1st gear, and rev to 30-40mph. Next select 5th gear and rev to 30-40mph. Is the frequency/noise of vibes the same?? If it is then it's transmission. If not then engine.

 

Robert

many thanks for everyones advice so far theres a few good things to check i would just say that when driving the car and i reach vibes say going down hill i can press the clutch and the vibes dont go would this eliminate one source of vibration ? plus when car was on axle stands i disconnected the prop completly and just briefly revved engine and there was no vibration at all does this meen engine ok i hope so oh and when someone mentioned half shafts what is the best way to check them together with back axle thanks again mark

just a quick thought if it is engine

1 what would that indicate

2 could it be engine mounts

3 if its gearbox related what is the next step and will i need a second mortgage

Dipping the clutch and the vibration remaining indicates the vibration is anywhere from wheels to clutch. I.E. engine NOT making vibes. Disconnecting prop and running engine & gearbox without vibes means these two components are balanced.

 

If you say the prop has been balanced twice it can't be that. Was it static balancing or dynamic??

 

Whatever is after prop I.E. rear diff and half shafts must be at fault.

Go through the problem methodically, eliminate each component and you should end up with those three (diff + 2 shafts).

 

Put the car up on stands again, remove the wheels (for a better view) and have a look at the half shafts to see if they are running out.

 

Has the car been crashed?

Shaft bent in crash and not replaced??

 

Just food for thought. Just take a methodical view, and you will sort it!

 

Regards

 

Robert

i have just turned the prop 180 seems to be slightly better what i ahve noticed is that when the car is spun up on axle stands this seems to amplify the vibration when out on the road it isnt quite so bad