Shuddering / Juddering

Post by **Mrben88** » 11 Aug 2006, 14:51

Hi,

New to this all, but van seems to have weird habit of occasional shuddering / juddering at speeds between about 50 and 65. It's a 1980 2.0L Aircooled.

Doesn't happen all the time and if you ease of the accelerator and then put foot back down that usually cures it, but quite worrying.

Any help appreciated.

Post by **SplendiferousII** » 11 Aug 2006, 15:33

Check your drive shaft fixings

Post by **HarryMann** » 11 Aug 2006, 15:39

Van or engine is source of this?

Definitely as spledierous says, check driveshaft flange bolts and CVJs first - asap.

Post by **Mrben88** » 11 Aug 2006, 15:51

Thanks

Not sure if it's van or engine as not consistent when it happens.

Is checking the driveshaft flange bolts and CVJs (what are they?) first something an idiot with a haynes manual and no idea could do on my drive?

What are the potential consequences?

Ben

PS - what am I checking for?

Post by **OLD ONE** » 11 Aug 2006, 15:53

Serious

Post by **OLD ONE** » 11 Aug 2006, 15:59

Each side of your gear box are the drive shafts, that connect the g/box to the wheels.
Grab hold of these and give a good shake, also where they fit to g/box are bolts. Make sure these are tight

Post by **Mrben88** » 11 Aug 2006, 16:09

OLD ONE wrote:Each side of your gear box are the drive shafts, that connect the g/box to the wheels.
Grab hold of these and give a good shake, also where they fit to g/box are bolts. Make sure these are tight

When I shake them, I'm presuming they shouldn't move?

If they do is tightening the bolts the solution?

(apologies for being clueless, but am hopefully going on a maintenance course in September)

Post by **R0B** » 11 Aug 2006, 16:15

if they are loose tighten them.otherwise they can snap.and believe me that can be a right pain.(yes it happened to me)

is tightening the bolts the solution

Post by **OLD ONE** » 11 Aug 2006, 16:26

They should not move up or down nor back to front, but you will have left to right(all of this is facing front or rear of van) If the bolts are loose, after you tighten them ,do another check to determine the state of your C/V joints(the bits inside the rubber boot each end of drive shaft)

PS fill in your profile, and you may get some one decide to come and have a look

Post by **Mrben88** » 11 Aug 2006, 16:36

OLD ONE wrote:They should not move up or down nor back to front, but you will have left to right(all of this is facing front or rear of van) If the bolts are loose, after you tighten them ,do another check to determine the state of your C/V joints(the bits inside the rubber boot each end of drive shaft)

PS fill in your profile, and you may get some one decide to come and have a look

Great - will give that a go over the weekend.

Hoping to get down to Shoreham if there's wind so may be able to test improvement then.

Thanks for all help so far and have put more info in profile.

Post by **HarryMann** » 11 Aug 2006, 21:56

So that'd be sailing, windsurfing, hang-gliding or just pi$$ing in the wind?

Wear gloves to check that shaft, get a good grip and as The Old One says, side to side is OK (drivehsaft splined into CVJs through the boots), up-down and fore-aft bad, also rotational play (clunking) bad of course. Look for split boots and black grease coming out. Can squeeze boots gently to force grease back into joints to prolong life (one inboard, one outboard inside the suspension radius arm, pe side).

Then check all 6 bolts of each joint, most likely to be loose will be those on inboard joint but check them all visually at least.
Two types of bolt head, hex socket cap heads, or 12-point spline drive (No. 8 size I think). Need suitable bit for your socket set. You do have a full socket set, 3/8" or 1/2" sq. drive metric, a must really, if you own one of these vehicles.

Torque is 28~33 ft-lbs, 30 will do. Failing a torque wrench, if any are loose at least tighten them up (40 lb pull on an 8" wrench, don't hang on it with all your weight) and clean out the socket heads before inserting the bit and keep the bit dead straight into the socket. Inspect for mulleringitis before tightening and be circumspect about tightening if animals have been at them.

Good luck, and make sure you pi$$ to leeward

Post by **Mrben88** » 14 Aug 2006, 13:21

HarryMann wrote:So that'd be sailing, windsurfing, hang-gliding or just pi$$ing in the wind?

Kitesurfing's the hope, but this summer has been more like pissing in the wind.

Right, gave them a shake and only seem to go side to side. Bolts seem pretty tight but will give them another go when I can get a proper socket set.

Boots look ok with no visible splits

No sign of mulleringitis - although that be obvious immediately.

In other good news, finally got the fridge to light and seems to be getting cold - although would have been better if it would have lit whilst we were away for two weeks.

Anyway, - if there is no play in the CVj's and the bolts are tight enough, any other ideas on what might be causing the shuddering?

Ta

Post by **HarryMann** » 14 Aug 2006, 17:04

We need a bit more information, better description really.

Do you mean a vibration, as in a wheel imbalance?
Any balance weights missing, that speed is typical and if it is you might feel something very slight when rolling along stedaily at exactly half that speed and of course, double it!

Are your engine mounts in good nick, have you taken a good look and/or levered them around lately?

Does it do it:
Rolling along in neutral
Engine off (be careful with that ignition key)
On overrun; under power;
Following wind, headwind, tacking

Post by **Diamond Hell** » 14 Aug 2006, 23:15

If it's juddering it could be something like carb icing - check that all of the intake hosing to the carb is intact, including any cold/hot air diversion devices.

Post by **Mrben88** » 15 Aug 2006, 10:45

Hmm,

Ok, better description.

This is our first vehicle.

Having lived in London for 6 years, we are only just now able to afford it so when it comes to engine mounts, CVJ's, Carb intakes etc I'm completely clueless, but trying to learn quickly. Hence my inordinate joy at getting something as simple as the fridge working.

As for the problem, I've no idea what a vibration due to wheel imbalance would feel like but the shuddering seems to be quite violent and more forward and backwards rather than side to side. It's also not consistent so you could be quite happily going along at 60 - 70mph when it will start.

If you ease off the acclerator it stops and then you can build up speed again.

Would say most common time for it to happen is at just over 65mph. haven't tried it in neutral / Engine off, but thinking it probably doesn't as if lift foot of accelerator it stops - same as neutral? Also a bit nervous about turning the engine off at 65mph

What's Overrun?

Have thought it might be an under power thing - could that cause it?

difficult to say on the wind situation as forgot to pack the spinnaker for our first trip....

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