I have been working to find and fix a hard knocking under my car when I launch hard. It sounded like it was coming from the under side of the passenger seat.
I replaced the subframe busahings (needed it anyway) and the Trailing Arm Bushings (wanted to try Urethane), but still had the knock. I got under my car again last week amd saw that the GUibo looked like it had a crack.
Today I replaced the Guibo. Unbelivable.. It was cracked through in one place, had a deep adjacent crack and every single bolt hole had cracks on both sides. Small wonder I was getting noise. The new one is in and she is smooth and fine. Damn near spun my car out accelerating onto the freeway coming out of a hard curving onramp (280 NB at Foothill for those from around here). This is a long curved ramp and I am usually going about 60+ by the time I get to the main road. I was in 3rd and juiced it and...Yahoo! Ride'm cowboy.. that back end broke loose and started to come around in a hurry.. I let off and managed to save it..If the back end of the Euro is light, at least it's predictable..Whew!
Car now is officially fixed.
S
Under Car Knocking under hard first gear launch
Moderators: GRNSHRK, ron, bfons
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UKDaveJ
Re: Under Car Knocking under hard first gear launch
Excellent - you must be pleased to have solved your knock!ScottAndrews wrote:I have been working to find and fix a hard knocking under my car when I launch hard. It sounded like it was coming from the under side of the passenger seat.
I replaced the subframe busahings (needed it anyway) and the Trailing Arm Bushings (wanted to try Urethane), but still had the knock. I got under my car again last week amd saw that the GUibo looked like it had a crack.
Today I replaced the Guibo. Unbelivable.. It was cracked through in one place, had a deep adjacent crack and every single bolt hole had cracks on both sides. Small wonder I was getting noise. The new one is in and she is smooth and fine. Damn near spun my car out accelerating onto the freeway coming out of a hard curving onramp (280 NB at Foothill for those from around here). This is a long curved ramp and I am usually going about 60+ by the time I get to the main road. I was in 3rd and juiced it and...Yahoo! Ride'm cowboy.. that back end broke loose and started to come around in a hurry.. I let off and managed to save it..If the back end of the Euro is light, at least it's predictable..Whew!
Car now is officially fixed.
S
Do you have any pics you can post of the damaged offending article?
I still havn't got around to changing my diff mount, I get a loud knock on full-blooded starts which definitely sounds likes its coming from in/under the boot. Mine doesn't sound like the same problem source, as its nowhere near the passenger seat, or should I say drivers seat on mine!!
Glad you didn't stack your car! Has yours' got an LSD?
Cheers,
Dave
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horsetan
Re: Under Car Knocking under hard first gear launch
Funny, that. Have never had this at all, in all the years I've had my '83. The last time it was ever launched from standing start was at Santa Pod in July last....UKDaveJ wrote:....I get a loud knock on full-blooded starts which definitely sounds likes its coming from in/under the boot....
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ScottAndrews
I would definitely check the Guibo. I was really surprised to find that this was the issue since the noise was DEFINITELY out back...
I think what happens is that the guibo flexes and this causes the front half of the shaft to go all loopy, and that gets transferred back to the rear shaft. On very close inspection, I can see that the back half of the shaft has rubbed a tiny bit on the edge of the exhaust resonator. This part is literally about 1.5 inches from the driveline, so I suspect the center bearing gives enough under these loopy conditions to allow the contact.
I tossed the Guibo. It is a round rubber doughnut with six metal reinforced holes. that engage the trans output shaft and the front flange of the drive line.
Scott
I think what happens is that the guibo flexes and this causes the front half of the shaft to go all loopy, and that gets transferred back to the rear shaft. On very close inspection, I can see that the back half of the shaft has rubbed a tiny bit on the edge of the exhaust resonator. This part is literally about 1.5 inches from the driveline, so I suspect the center bearing gives enough under these loopy conditions to allow the contact.
I tossed the Guibo. It is a round rubber doughnut with six metal reinforced holes. that engage the trans output shaft and the front flange of the drive line.
Scott
Hi Scott,
Glad you got your guibo sorted. Pesky little blighters, when they give out.... Incidentally, the whole engine tranny and exhaust are on the move under hard acceleration, and this will help things to knock about under there too. Might be symptomatic of worn engine/gearbox mounts- these will give your guibo a hard time too.
Despite me being a Brit and living in the UK I have probably driven that very ramp onto 280 on one of my occasional trips to your part of the World. Was it damp when you had your 'moment' ? From what I recall, parts of the roads thereabouts are a bit worn from sheer volume of traffic, so are occasionally 'interesting' even in the dry. However, things get very sketchy indeed when it rains from what I remember....
Cheers
Glad you got your guibo sorted. Pesky little blighters, when they give out.... Incidentally, the whole engine tranny and exhaust are on the move under hard acceleration, and this will help things to knock about under there too. Might be symptomatic of worn engine/gearbox mounts- these will give your guibo a hard time too.
Despite me being a Brit and living in the UK I have probably driven that very ramp onto 280 on one of my occasional trips to your part of the World. Was it damp when you had your 'moment' ? From what I recall, parts of the roads thereabouts are a bit worn from sheer volume of traffic, so are occasionally 'interesting' even in the dry. However, things get very sketchy indeed when it rains from what I remember....
Cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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ScottAndrews
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UKDaveJ
You are not running metricsScottAndrews wrote:Nope..Dry as a bone..The Euro has really great torque, so under just about any cornering condition I have to be rather cautious about juicing the gas or it breaks loose. I think I may need new rear tires, and hopefully that will help a bit. That, and maybe some sandbags under the rear seats!
S
are you Scott? 
That would explain it.....
Are you running an LSD?
Dave
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ScottAndrews
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craigt
I've had the same knocking for a while, started out as a slight vibration and then got steadily worse. I'ts the next 'big' job on my car.
Looking underneath the centre bearing/mount looks okay, my shaft does not have guibo's so I can only assume it's the uj's and/or the shaft has gone seriously out of balance.
Can guibo's be retro-fitted, or is the entire shaft assembly different ?
Anybody got an idea how much it would cost to get the entire shaft reconditioned and balanced ?
Many thanks
Looking underneath the centre bearing/mount looks okay, my shaft does not have guibo's so I can only assume it's the uj's and/or the shaft has gone seriously out of balance.
Can guibo's be retro-fitted, or is the entire shaft assembly different ?
Anybody got an idea how much it would cost to get the entire shaft reconditioned and balanced ?
Many thanks
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ScottAndrews
Why don't you have a Guibo? I thoght all 6ers have them.
I got an entirely new driveline from some guys in Portland OR. THey advertise in Roundel. Not sure what your options are in the UK. The cost for a rebuilt one is about $475 including a $75 core charge. THe new one, from the dealer is, I belive about $550, and it includes a Guibo.
S
I got an entirely new driveline from some guys in Portland OR. THey advertise in Roundel. Not sure what your options are in the UK. The cost for a rebuilt one is about $475 including a $75 core charge. THe new one, from the dealer is, I belive about $550, and it includes a Guibo.
S
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horsetan
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UKDaveJ
Guibo confusion
If that one is for a manual, what do the ones for the auto look like?
Dave
Dave
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ScottAndrews
CRAIG T
CraigT..
I have a theory that someone pulled your guibo when it went bad. They then probably jusdt bolted the driveline directly to the rans output flange. This is possible because the drive line has an adjustment for length.
Just behind the center bearing the driveline has a hex cap that can be unscrewed. When it is loose, it allows the shaft to extend or contract along an internal spline. The idea is that you loosen this when putting in a guibo, or when re-installing the drive line after any significant work has been done. You tighten up all the bolts on either end, and then tighten the shaft hex cap to log the shaft at the length it has chosen. It allows the driveline to settle to exactly the right length.
I suspect someone tossed the guibo and adjusted the driveline to compensate for the lack of about 1.25 inches in the assembly. The only problem from this (other than the loss of the damping qualities of the guibo) is that the shaft is probably too far extended and this not as rigid as it should be...That, and the center bearing is probably all distorted.
So, get under your car; Look at the center bearing. Is it all the way forward and maybe streched (the rubber surround that holds the bearing proper)? If so, then remove the two 13 mm nuts that hold the bearing, Undo the shaft at the drans end, and loosen the center hex cap I mentioned earlier. Can you slide the front shaft back enough to gat about an inch or so of clearance between the trans flange and the driveline flange? If so, then go buy a Guibo (use the dealer to be sure you get a good one). Mine cost about $60. You might as well order six bolts at the same time, since if your car was set up flange-to-flange then the bolts they used will be too short.
Remember to pre load the center bearing, and don't forget to tighten the center hex cap.
S
I have a theory that someone pulled your guibo when it went bad. They then probably jusdt bolted the driveline directly to the rans output flange. This is possible because the drive line has an adjustment for length.
Just behind the center bearing the driveline has a hex cap that can be unscrewed. When it is loose, it allows the shaft to extend or contract along an internal spline. The idea is that you loosen this when putting in a guibo, or when re-installing the drive line after any significant work has been done. You tighten up all the bolts on either end, and then tighten the shaft hex cap to log the shaft at the length it has chosen. It allows the driveline to settle to exactly the right length.
I suspect someone tossed the guibo and adjusted the driveline to compensate for the lack of about 1.25 inches in the assembly. The only problem from this (other than the loss of the damping qualities of the guibo) is that the shaft is probably too far extended and this not as rigid as it should be...That, and the center bearing is probably all distorted.
So, get under your car; Look at the center bearing. Is it all the way forward and maybe streched (the rubber surround that holds the bearing proper)? If so, then remove the two 13 mm nuts that hold the bearing, Undo the shaft at the drans end, and loosen the center hex cap I mentioned earlier. Can you slide the front shaft back enough to gat about an inch or so of clearance between the trans flange and the driveline flange? If so, then go buy a Guibo (use the dealer to be sure you get a good one). Mine cost about $60. You might as well order six bolts at the same time, since if your car was set up flange-to-flange then the bolts they used will be too short.
Remember to pre load the center bearing, and don't forget to tighten the center hex cap.
S
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craigt
) does nothing for me.-
snow shark
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UKDaveJ
What no guibo?!
I'd guess that with an auto you dont get the same kind of driveline 'shunt' that you get with a manual tranny?!snow shark wrote:My 87 auto box has no guibo either. I actually looked under a number of 6's with autos, later cars all, and none had them.
Rik
Dave
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snow shark
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craigt
The parts database shows both types, both with the same part number :? :?
http://www.realoem.com/bmw/showparts.do ... g=26&fg=05
http://www.realoem.com/bmw/showparts.do ... g=26&fg=05
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UKDaveJ
The guibo-equipped one is listed as no.1 in the diagramcraigt wrote:The parts database shows both types, both with the same part number :? :?
http://www.realoem.com/bmw/showparts.do ... g=26&fg=05
The one with the uj is listed as no2. in the diagram
In the little box below it refers to ONLY no.2.
There is no reference to no.1 in the databox....hmm, i'm confused now as well.....
:? I would have said that no.1 = manual box, no.2 = auto box!
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craigt
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ScottAndrews
You can easily (well, sorta) determine if the u-Joints are bad. YOu have to remove the driveline and physically feel the joint. If they are loose, or binding (more usual), then you have to eithe replace or rebuiild the driveline.
More typical is that the center bearing is shot. This is a bearing that is held by a rubber diaphragm. Usually the diaphragm is shot and this means the center is not very well restrained.
All of this will be apparent on removal and inspection of the driveline. This is an easy job...takes about 30-40 mins.
S
More typical is that the center bearing is shot. This is a bearing that is held by a rubber diaphragm. Usually the diaphragm is shot and this means the center is not very well restrained.
All of this will be apparent on removal and inspection of the driveline. This is an easy job...takes about 30-40 mins.
S
Sandbags under the rear seats? Yes, not a bad idea.
Either that or in the centre of the spare wheel somewhere.
When Jaguar saloons (fitted with the Le Mans winning XK engine) became popular, South London (local pron. Sarf Laahndun) wide boys would keep the back end on the road with the careful addition of a bag of cement. This has the benefit of eventually going solid in our damp climate, moulded perfectly to the space it fits in.
On the other hand my Grandfather (who at some point or other owned an example of just about everything that had an engine in it and went like stink, from an Indian sidecar outfit with a driven third wheel, price 10', to various Jags, Bentleys etc) was a Hampshire Country Boy. No cement for him, oh no... -he used bags of fertiliser instead.
Cheers
Either that or in the centre of the spare wheel somewhere.
When Jaguar saloons (fitted with the Le Mans winning XK engine) became popular, South London (local pron. Sarf Laahndun) wide boys would keep the back end on the road with the careful addition of a bag of cement. This has the benefit of eventually going solid in our damp climate, moulded perfectly to the space it fits in.
On the other hand my Grandfather (who at some point or other owned an example of just about everything that had an engine in it and went like stink, from an Indian sidecar outfit with a driven third wheel, price 10', to various Jags, Bentleys etc) was a Hampshire Country Boy. No cement for him, oh no... -he used bags of fertiliser instead.
Cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Knocking and holding back end down
Many years ago(oh alright in the 60s) I had an ex-Metropolitan police Wolsely 6/80.This had two boxes welded to the rear axle filled with concrete.It certainly improved the rear end.Here endeth the the lesson.
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UKDaveJ
***FAO Ron & Brucey***
Maybe I'm being really thick, but I don't see what bags of sand, cement or fertiliser have to do with knocks from under the car?? :?
For traction I can understand, as i can with handling (to an extent, re-distribution of weight is better if weight cannot be removed)
Cheers,
Dave
Maybe I'm being really thick, but I don't see what bags of sand, cement or fertiliser have to do with knocks from under the car?? :?
For traction I can understand, as i can with handling (to an extent, re-distribution of weight is better if weight cannot be removed)
Cheers,
Dave
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ScottAndrews
Traction (was thumping in back...)
THis thread has sort of drifted off into a different subject.
My concern with putting to much weight way back inthe trunbk is that I had to rebuild the entire trunk cross member once. Ut had cracked. At the time I joke that the PO must have put a coupl eof bags of cenet in the trunk... Now I suspect that is exactly what led to the poor broken down trunk.
The rear seats, however might be great candidates.
In a related post on BCG a few months back it was postulated that the LSD equipped cars were mush more prone to throttle base back end "liveliness". The issue apparently is that the non-LSD cars will always spin one wheel, so that wheel will lose traction, while the other wheel will keep the rear end from flying around on you..
What this tells me is that my back tires are not up to the job given the torque my baby is able to lay down. I think I'mheading toward asymmetrical tires... I run 225/50/16's on 16x8 rims now, I wonder if I can get 245's on the same rims and run them on the back.... Hmmm
S
My concern with putting to much weight way back inthe trunbk is that I had to rebuild the entire trunk cross member once. Ut had cracked. At the time I joke that the PO must have put a coupl eof bags of cenet in the trunk... Now I suspect that is exactly what led to the poor broken down trunk.
The rear seats, however might be great candidates.
In a related post on BCG a few months back it was postulated that the LSD equipped cars were mush more prone to throttle base back end "liveliness". The issue apparently is that the non-LSD cars will always spin one wheel, so that wheel will lose traction, while the other wheel will keep the rear end from flying around on you..
What this tells me is that my back tires are not up to the job given the torque my baby is able to lay down. I think I'mheading toward asymmetrical tires... I run 225/50/16's on 16x8 rims now, I wonder if I can get 245's on the same rims and run them on the back.... Hmmm
S