[SOLVED] Creak coming on and off throttle

[GulfSeven]

I'm getting a creak when accelerating and decelerating (and on a gear change). It sounds like it might be coming from near the diff. Are there any usual suspects for parts that might be interfering/rubbing in that area, or any particular bolts to check the tightness of??

 

[SM25T]

Sounds travel in very strange ways in a Caterham. Check all suspension and engine mount bolts.

[Grant_7]

Radius arms loose?

[GulfSeven]

Solved it - was the top front diff carrier bolt - the one that goes all the way through. Tightened it to 61Nm as per the assembly guide and it's all quiet now 

Any tips for getting it to stay tight if it's prone to loosening?

[Geoff Brown]

Replace the nyloc & Schnorr washers !

[Dixa1225]

Good advice from Geoff , 100% replace the Schnorr washers & nyloc 

[GulfSeven]

Do you think that's necessary on a car that's less than 2 years old and has covered 2,200 miles?

[ScottR400D]

Depends why it's come undone. If it was originally tightened correctly then either the washer or nut haven't done their job so should be replaced. If it wasn't then you might get away with just tightening. That's just a gamble though.

For what it would cost seems a no brainer to replace. 

It's really a matter of number of times they've been used not age, and even at only two years the diff may have been out and back in. How long have you had the car?

[GulfSeven]

I've had the car from new. It has gradually come loose and hasn't been removed.

[John Vine]

Re #7:

Well, you can re-use a Schnorr just once, and the Nyloc too if it resists being turned (with the fingers) onto the bolt.

However, I'd be asking why it came loose in the first place?   Personally, I'd renew them.

JV

[GulfSeven]

It looks like 2x M12 Schnorr washers and 1x Half Nyloc 1/2" "T" Type.

Where's good to supply? Caterham? Redline?

[John Vine]

Either would do.  They're not expensive bits.

If you're searching CC's Online Store, note that they have trouble spelling Schnorr (but you get a pack of 4 as a bonus).

JV

[ScottR400D]

You can find on eBay for 1/3 of the CC price. 

[GulfSeven]

#12 John, Is that the M12 washer? It doesn't specify. In fact, how did you even find that? You can't find it by searching, and if you go to the parent category (HOME>OTHER>FIXINGS>WASHERS) it isn't listed 

I think this is the Nyloc nut: https://caterhamparts.co.uk/nuts/284-nut-1-2-unf-half-nyloc.html

[Jonathan Kay]

Have you got John's amended drawing with the correct position of the Schnorr washers?

Jonathan

[John Vine]

Re #14:

I searched on "washer".  It's on row 5 (p/n 30Z1069A). The other Schnorr washers listed are described as M6 and M8 so I guessed it might be the M12!  And you're right, it doesn't specify a size.  Also, the Assembly Guide doesn't specify a part number to enable a cross-match.  Perhaps check with the Parts Dept?

Yes, that's the correct nut.

Re #15:

That's odd.  The explanatory text seems to be missing from that picture:

But it may not be relevant here as it refers to the lower bolts.

JV

 

[Geoff Brown]

As stated in #5 replace washers & nyloc. Either the nut & bolt not torqued up correctly on assembly at the factory or the nyloc & washers are faulty. I would put my money on the factory being limp wristed. 

As that is the case best to spanner check all fastenings at the back end JIC..........