odd sounds..

[edoh]

from rear underneath back of van....
hard to describe -
intermittent - doesnt happen when sitting idling -
doesnt seem to depend on travelling speed -
5 - 10 second bursts every few miles -
sounds like - thut thut thut thut thut etc
like a flapping gentle round of slaps!?!
not a mechanical or grinding sound -

checked wheel nuts secure - mud flaps not touching anything -
tyre pressures good -
what to check next?
any suggestions much appreciated -
edoh

[chrisbeck]

Possibly CV joint loose

[edoh]

will have a look -
thanks for the suggestion
where's that nice spacious warm centrally heated garage when you need one?

[Oldiebut goodie]

Exhaust blow as exhaust flexes?
CV joint noise is usually loud enough for you to stop immediately to check it out.

[edoh]

cheers - thats really useful -
i'm wondering whether it's exhaust related too -
more investigations to come

[what2do]

This reminds me of a thread I meant to type up relating to a problem I had. I had an intermittent problem that would occur, sometimes at the rear sometimes at the front, sometimes n/s or o/s. The tapping sound would increase with ground speed, tried in vane to find the culprit. Then it hit me, I have a gravel drive and a stone would lodge itself in the tyre treads and amazingly remain for quite a few miles. Seems obvious now but I was on the point of cursing infront of the kids!

[edoh]

loose cv joint bolts on on one side
tightened up both -
brrrrrrrrrr. .. .
cold -
but sorted
thanks for all your suggestions

[what2do]

That's what's known as a lucky escape.

[Oldiebut goodie]

You were lucky - caught it before the thud, thud, thud stage!

[itchyfeet]

loose cv joint bolts on on one side
tightened up both -
brrrrrrrrrr. .. .
cold -
but sorted
thanks for all your suggestions

With a torque wrench I hope, worth checking washers are fitted.

[CovKid]

Very very rare anyone catches a CV joint before it departs company - unless you've had it happen before and know the vague warnings you get. Glad you asked the question - next incident would have been an almighty 'bang' as the last two bolts go when you pull off. In my experience they always fail at busy junctions or in the dark and NEVER as you've just pulled into a garage.

[edoh]

washers in place and torqued up just so -

has happened before - so mindful of any unusual sounds from rear wheels -
last time - (as covkid notes) - busy A road - junction - night time - cold - dark -
tools at home! bang! bang! ambushed by me own van!

all well now

[itchyfeet]

If it's happened before so check them every year.

I'd replace bolts and washeres with new, not usual for them to just come loose unless, washers are wrong or flattened (special safety washers) or not torqued correctly, or dirt/excessive grease was trapped between mating surfaces and it's now moved.

[CovKid]

Good bolts help. No shortage of cheese ones around. A couple of years ago I latched on to a local source of high quality torx bolts supplied to the trade and I bought hundreds. Now I just fit new bolts if I ever remove or have to attend to a CV joint. Whether it warrants it or not is arguable but at least the heads will be in good condition then.

A lot of torque is put through those joints what with it being a heavy vehicle to move off. It only needs a chink in the armour (one loose bolt) and the rest ultimately follow. An annual check is advisable, like fuel hoses and bushes.