Clicking when rolling the car and stuttering when driving

[Scott Dabinett]

Have a knocking/clunking sounds from the rear.

 

We have a 2001 Caterham ex-megagrad race car. Has a LSD and straight cut type 9 box.

 

A little while ago we noticed that when we pushed the car in and out the garage there was a knocking coming from the back end. I could feel a bit of play in one of the axles so we replaced both of those. Still happened every now and again.

 

Tonight we went and got it out the trailer to check it over before a trackday in a couple of weeks. Rolled it in and out the garage and it was silent. I took it for a quick blast down the road. While I was driving steady letting it warm up it felt fine. I then turned around at a junction and it sounded like it was clicking as I was turning. I gave it some stick back down the road and it sounded like it was misfiring a little bit. I slowed down and thought I would take an easy drive back and every time I touched the throttle it would judder like it was misfiring but if I dipped the clutch and revved it would rev up absolutely fine but as soon as I let the clutch out and accelerated it would stutter again.

 

Put it back in the garage and jacked it up tried to see if anything was loose, only thing I could see was a bit of play where the propshaft went into the gearbox (don't think it was the UJ) and there seems to be quite alot of play in the diff as in you turn a rear wheel and it takes 50mm of a turn before the prop starts moving. Is this normal?

 

After having a look around I dropped it back down and took it up the road driving pretty slowly, prob not going over 20mph and it felt fine!

 

Anyone have any ideas? I'm tempted to get a couple of UJ's for the propshaft and try those just to eliminate it.

[ScottR400D]

I think you'd feel any undue okay in the UJs testing by hand. 

If I roll my car in the garage, when it's hot, it often makes a clicking/tapping sound, always has done. I believe it's the CV joints and nothing to worry about. 

The play at the wheel sounds about normal too, they're very sloppy and there is a lot of accumulated play between the diff and shafts. 

The clicking when turning hard could be the LSD and that could be worth looking at. No idea what make it would be at that age. 

[Scott Dabinett]

Hi Scott,

 

Cheers for confirming the play in the diff!

 

It was only put in 1 track day ago so it is near enough brand new! I'm wondering if something was not put together correctly!

[Geoff Brown]

Drive shaft CV joint worn ?

[Scott Dabinett]

Hi Geoff, it has just had 2 brand new drive shafts put in as I thought this was the issue!

[ScottR400D]

If you have anew diff and driveshafts, I would say it's just the normal noise! What LSD is it?

[ScottR400D]

As far as the 'stuttering' is concerned, could this be just having difficulty in driving it smoothly? They're not the easiest thing to do that with and it's easy to induce 'kangaroo' or jerky progress, with a very sensitive throttle and a sloppy drivetrain.

[Geoff Brown]

2nd try - rear brake pads 'sticking' then releasing as the disc rotates ?

Had this occurring with a front caliper until thoroughly cleaned & pad back plate copper greased.