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CSR Differential Removal - can't get the long top bolt out. Any ideas?


MarkTheGoose

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The diff is coming out of my 2005 CSR (probably for the first time ever) so that I can get the prop shaft out. Everything went swimmingly, bolts out of prop shaft at the front of the diff. Both bottom diff mounting bolts loosened. Suspension all dismantled. Drive shafts out of diff. Trolly jack with wooden block under diff. Nut removed from long bolt.

That all took around 45 minutes, with no problems anywhere.

I have now moved the bolt 163mm through the diff, but it needs to go 231mm for the diff to actually come out. It's the classic problem of the spacer now being an interference fit with the bolt. The bolt turns freely in the chassis and diff housing.

Lots of plus gas.

I've been drifting it out with an 11mm coach bolt and have now run out of length. I'm seriously considering cutting the bolt off near the chassis on the head end and then pushing it 50mm back the way it came, to clear the chassis. However, Caterham have no stock of the bolt and of course it's longer than the bolt from the de-dion chassis.

Suggestions on a postcard please

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It could be that a thin spacer shim has been dragged in between the bush and the bolt shaft (this happened on my car during diff removal). Tapping it back in a bit and getting lubricant down between the bolt and bush can help, then tapping it out again and repeating with the in/out motion. I used a 10mm (could have been 3/8") piece of steel rod slightly longer than the length of the bolt to tap the bolt out.

This is what a couple of my spacers looked like after being dragged in between the bolt and bush:

DSCN0070.JPG.dd4de3bd49e627d6e67c68f688221acc.JPG

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@Aerobod - helpful, thank you. It does seem to be that bashing it back is currently easier than bashing it out. BUT, bashing is the operative word. @Wrightpayne - I did try a piece of mild steel threaded bar - it ended up completely splayed out at the end and then just bent. The forces are pretty huge, I'm bashing as hard as I can with a club hammer. I'm currently trying to see if I can source a long cylinder head stud for the job - both bashing and ultimately reassembling, with a nut on each end. Thanks for your suggestions guys

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Had similar problem a few months ago. Can't remember what I used as a drift but had to use something that allowed me to get out from under the wheel arch and give it a decent "tap". Worked back and forth from each side and turned and used Plusgas. Was just slight corrosion that caused it to bind. 

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@Grebby, thank you for your generous offer!

@Scott - I'll give Red Line a call this morning. To be fair to Caterham, when I spoke to them, they said that they had sold one in the last 3 years and so it dissapeared from stock in a rationalisation exercise. Darren at Caterham has also said I should call this morning as he has a Plan B solution that they now use when assembling CSRs for Europe.

@David - I do remember when we were exchanging around your propshaft you told me that the top bolt was a real pain to remove. I'm certainly going to go try the backwards / plus gas / forwards / plus gas approach today - decent "tap" *rofl*

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Mark, had another look at our earlier postings to remind myself what I did. I was reminded that the bolt was seized on the bushes and would rotate 45deg and spring back. Here is what I did: "Several socket extensions allowed me to get out from under the wheel arch and get a decent lever on the long bolt and get it turning. This eventually, with Plusgas and thumping, allowed me to get the bolt out, drop the diff and release the propshaft"

Hope you have success, David

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Thanks all for your support - James you're comment especially resonates. Stuff shouldn't be as tricky as it is, but I did choose to buy a 15 year old car! Anyway - the bolt is out. Having drifted it out just over 6 inches, even bashing it in & out again, it seemed to get to a point where it wasn't going any further and so I threw the towel in and cut through it with a dremmel, close to the chassis, about half way along the length of the bolt. It then took about 2 minutes to bash it back a couple of inches to clear the chassis and I was then able to drop the diff and withdraw the the cut off bit of bolt. It was a relatively loose fit in both of the bushes (chassis mount points) and quite loose in the diff housing. It was very very tight in the 2 inch spacer!

IMG_4310.jpg.16bf4b7c6d0c36fe4a80135905c2e1c2.jpg

I put the cut off bit, on the vice loosely, with the spacer above the jaws and used a club hammer to knock it out of the spacer. It took at least 10 big hits from the club hammer to move it. No wonder it was hard. It's actually a silly design, there is no need for the spacer (which is only ever loaded on it's ends) to be such a tight fit - I'm tempted to actually run a drill down all three of them, so that there is no way it can get stuck again.

Anyway, at that point the diff is no longer attached to the car anywhere, so I just simply lowered it out through the chassis top the floor - except I didn't! I cannot figure out how to get it out. To be fair, I think that I just run out of strength and trying to juggle on the trolley jack with nobody manouvering the front flange end proved too hard. I have a helper coming tomorrow to give me a hand, so hopefully it will be out tomorrow and I can start on the propshaft.

 

IMG_4318.jpg.152862a883dd8b3cb5c1421936b97a89.jpg

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The other bit of excitement is I touched the fuel hose with the dremmel cutting disc spinning at 30,000 rpm and so to be on the safe side, I need to replace a short length of fuel hose - Does anyone know if this piece with the screw fitting on one end and a jubilee clip on the other a standard part?

IMG_4314.jpg.1bc259c091a1e1505ef75b4de7cb4cc1.jpg

In other news, Darren at Caterham cars has come up trumps. He's sending me a specially machined head stud and two nuts & washers, which is how they now do CSRs at the factory.

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Fuel hose:

Whilst you have good access I would change all the rubber hoses for new see the post below, unions can be reused as you can cut the swaged part off which leaves a male barb, push the new hose on and secure with Oetiker clips (O clips) as they offer a more uniform constriction on the hose.

https://www.lotus7.club/forum/techtalk/fuel-hose-time-check-yours

 

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When putting the diff back in use proper washers:

top through bolt (usually half inch)

https://caterhamparts.co.uk/washers/282-washer-1-2-x-11-8-chamfered-plain.html?search_query=washer+1%2F2&results=476

bottom side bolts next to the prop connection (usually M12)

https://caterhamparts.co.uk/washers/942-washer-m12-plain.html?search_query=M12+bolt&results=246

 

Don't use small thin washers - they are s**t and cause trouble. 

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Igor, thanks. Caterham sent me nylocs and proper washers with the new top stud...

Propshaft is back with new bearings and balance and the hope is that it will all be going back in the car today. I did a test fit of the propshaft last night and it refused to slide onto the gearbox splines - is there a knack to this?

David, I feel your pain

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