Hi All,
I had the front donut/guibo replaced which left me with a vibration through the driveshaft, felt like it was going to enter the car through the floor pan! So, took it back and got the centre carrier bearing replaced on the garage's advice and now still have the vibration. Only occurs in 1st gear under moderate/hard acceleration off the line and still bangs and shudders on the floor pan. Now the garage tell me the subframe bushes must be the culprit and want me to pay to have those replaced as well.
The car had no vibration at all before all of this, it's a 325 Sport, any ideas? Cheers.
Driveshaft vibration
Moderator: martauto
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mrLEE30
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If it was not vibrating before the replaced the flex coupling then i suspect they did not put it back together correctly. they must preload the centre bearing. 1. slide centre bearing on shaft and bolt into fixings LOOSELY. 2. fix the rear of the shaft to the diff ensuring its centred, tighten bolts,3. fix the flexible coupling and shaft to the gearbox ensure its centred, tighten bolts.4. then slide the centre bearing 4-6mm toward the gearbox and tighten bolts in that position.
This will cure 90% of peoples vibration probs. IF not then ask if your garage split the two ends of the prop shaft without marking its original spline position, if they did then your shaft is now out of balance. it must be balanced on a machine by rotating the two shafts in their splines until its balanced, or the same can be done on the car. VERY time consuming and if the garage screwed it up they shold be made to put it right on THEIR time as its extreamly basic mechanic knowledge not to split a prop shaft without marking the spline positions.
if all the above does not solve vibration probs then suspect the problem with the centre U-joint. they can be replaced but would be easier to get a new prop from a scrappies.
I personally doubt the sub frame bushes would cause this problem, banging yes (but that would normally be the diff bushes), but vibration no.
mrlee
This will cure 90% of peoples vibration probs. IF not then ask if your garage split the two ends of the prop shaft without marking its original spline position, if they did then your shaft is now out of balance. it must be balanced on a machine by rotating the two shafts in their splines until its balanced, or the same can be done on the car. VERY time consuming and if the garage screwed it up they shold be made to put it right on THEIR time as its extreamly basic mechanic knowledge not to split a prop shaft without marking the spline positions.
if all the above does not solve vibration probs then suspect the problem with the centre U-joint. they can be replaced but would be easier to get a new prop from a scrappies.
I personally doubt the sub frame bushes would cause this problem, banging yes (but that would normally be the diff bushes), but vibration no.
mrlee
Cheers, I tried the preloading the centre with them and that made no difference. They do know what they're doing (I assume, main guy used to work at Sytner BM in London), but reckon it's the subframe bushes. I'll ask about the prop being split as I'm sure it's something they've done. Car had nothing wrong before, now supposedly bits are failing causing the same symptoms/problems? Call me a cynic, 'cause I find that hard to swallow.
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mrLEE30
- E30 Zone Team Member
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- Joined: Tue Jan 18, 2005 11:00 pm
- Location: Sweating buckets in Bahrain
just cause he worked at any dealer does not mean anything!!! he could have made the tea for all you know. and most dealers do not fix anything these days, they only replace what a computer tell them to replace, but thats me being cynical too i am sure there are lots of good dealer mechanics out there 
check the following first
1.engine and transmission mounts - visual chack prop on car
2.UV joint worn or siezed - visual check prop on car - pull and twist the prop and check for play in the UJ joint...see below
3. the sliding coupling may have seized - prop off job - grease if necessary
4. the front centreing guide is worn - prop off job and see below
according to our friend the Bentley manual
play in UJ joints max 0.15mm
front transmission guide tolerances : axial play on the output transmission flange 0.10mm
radial play on the transmission flange 0.07mm and same on the diff flange.
please let me know once you fix the problem as i cannot see how the subframe bushes can cause propshaft vibration as you describe, as i said MAYBE the diff bushes but not really too convinced even on that.
It seems too strange that 99% of propshaft virbration is to do directly with the prop itself and output/input flanges and fitting of the prop.
you had no vibration before they did any work, then they remove the prop and hey presto you have vibration probs. not convinced it is the bushes. hence why i ask you to keep us informed.
good luck mate
mrlee
check the following first
1.engine and transmission mounts - visual chack prop on car
2.UV joint worn or siezed - visual check prop on car - pull and twist the prop and check for play in the UJ joint...see below
3. the sliding coupling may have seized - prop off job - grease if necessary
4. the front centreing guide is worn - prop off job and see below
according to our friend the Bentley manual
play in UJ joints max 0.15mm
front transmission guide tolerances : axial play on the output transmission flange 0.10mm
radial play on the transmission flange 0.07mm and same on the diff flange.
please let me know once you fix the problem as i cannot see how the subframe bushes can cause propshaft vibration as you describe, as i said MAYBE the diff bushes but not really too convinced even on that.
It seems too strange that 99% of propshaft virbration is to do directly with the prop itself and output/input flanges and fitting of the prop.
you had no vibration before they did any work, then they remove the prop and hey presto you have vibration probs. not convinced it is the bushes. hence why i ask you to keep us informed.
good luck mate
mrlee
Will keep you informed, gearbox mounts just replaced, so will rule them out. Sliding coupling, I assume you mean the carrier bearing? That's fine also, have seen it myself, will try the rest. Pretty sure UJ is ok also. Without stands/tools/somewhere to work on it, on a daily driver, it's a bit of a mission. Drove perfect until recently even with 178k miles. . . . Thanks for the suggestions.
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mrLEE30
- E30 Zone Team Member
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- Joined: Tue Jan 18, 2005 11:00 pm
- Location: Sweating buckets in Bahrain
no when i say sliding coupling i mean the joint between the two halves of the prop. there is a front shaft section with the UV joint, then centre bearing, then a coupling to hold the two halves together and the rear (longer)section of the shaft. this coupling has splines. these splines must be greased to allow then to slip slightly forwards and backwards. AND if you ever split a prop mark the position before you open it. they are balanced in the factory with small weights welded in the necessary location (the weights look like large postage stamp sized pieces of metal) the props are joined together and then balanced. if you split the front and rear portion of the prop and do not re-join then in EXACTLY the same spline location it will unbalance the prop. This was what i was refering to in my first post
This i am almost sure will be the problem (or the UV joint and note there is almost no play allowed)
Oh yeah a cheating way to balance a prop if this is the case is to put a large jubilee clip round it. (sometimes two with the two clip fastening locations in the same place) test the car, if vibrations then get underneath and rotate the two clips by 45degrees, test again and repeat until vibration goes. essentially you are using the fastener section of the jubilee clip as a balancing weight. try one first and if no luck use two. it works best as you only need to remove the exhaust shield to get access to the clips.make sure the clips are tight though!!!!
good luck!!!
to rebalance it you must either 1. add new weights 2. trial and error you must fit the prop, test it and if still has vibration you must turn the prop one spline and test again!!! hence why it will take a long time!!! you must remove exhaust/heat shield each time remove the rear of the prop from the diff, undo the coupling nut, and rotate one spline!!, put back together and drive it. there are probably 30-40 splines so do the maths, a couple of hours a spline =IF not then ask if your garage split the two ends of the prop shaft without marking its original spline position, if they did then your shaft is now out of balance
This i am almost sure will be the problem (or the UV joint and note there is almost no play allowed)
Oh yeah a cheating way to balance a prop if this is the case is to put a large jubilee clip round it. (sometimes two with the two clip fastening locations in the same place) test the car, if vibrations then get underneath and rotate the two clips by 45degrees, test again and repeat until vibration goes. essentially you are using the fastener section of the jubilee clip as a balancing weight. try one first and if no luck use two. it works best as you only need to remove the exhaust shield to get access to the clips.make sure the clips are tight though!!!!
good luck!!!