New build - fitting differential. UPDATED: resolution

[gwiddicombe]

Had one of those days today when things didn't seem to go right. Had a go at fitting the differential in my Rover based kit. I got the top bolt through, but when it came to lining the prop shaft up with the differential, the lower bolts were about 4cm from where they should enter the chassis mountings.

 

I'm obviously doing something incorrectly here (quite drastically by the look of it), but I can't figure it out. It's almost as if the prop shaft is too long (which can't be the case as the prop shaft appears to be the same on all cars ??) or the diff itself is incorrect (which again can't really be the case can it?).

 

Decided to call it a day before I did some damage (to myself or the car!), but any advice in fitting this would be appreciated. I've had a search for on the forums but can't see this problem mentioned.

 

Cheers,

 

G

 

My Caterham Build Diary available here

 

Edited by - gwiddicombe on 25 Oct 2007 18:09:43

 

Edited by - gwiddicombe on 1 Nov 2007 08:12:51

[caterhamnut]

Any pics?

I may be missing something, but is the prop fully located into the back of the gearbox?

 

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[gwiddicombe]

No pics I'm afraid (I didn't get a chance to take any of this), although the prop is fully located into the gear box in that the prop 'housing' (for want of a better word) is flush with the gearbox tail.

 

The prop is inserted into the gearbox tail by passing it down through the car. I.E., it hasn't been passed upwards through the car where it would then be too low to engage properly with the diff.

 

My Caterham Build Diary available here

[Roadsport06]

I think a pic would be very helpful. If you have the prop in the tunnel and the diff mounted then the two should marry up.

Much easier to do without the g'box though, I'd have thought.

I think the SV does have a longer prop but they have stickers on them anyway, so easy to tell

 

BRG and Yellow nose VU06 XZX

 

[gwiddicombe]

Ok - I'll try and get a pic. It'll be a couple of days before I work on the car again.

 

Cheers,

 

G

 

My Caterham Build Diary available here

[7 wonders of the world]

Hi, The part numbers are on the prop, ISTR the build manual steers you to check you have the right prop to, S3 being shorter than SV before you fit it - just in case the wrong one has been assigned to your kit, seem to remember it being in the first few pages of the manual.

 

Good luck and enjoy 😬

 

Too young to be old !

[gwiddicombe]

I now have some photos available here

 

The page shows two photos:

1) The first one shows that the lower bolt holes on the diff and chassis do not line up with the top bolt located.

2) The second one shows that the lower bolt holes on the diff and chassis do not line up with the prop shaft located.

 

Does this make sense? It looks to me like the propshft is correct size, as it engages with the diff. However, I can't seem to line the lower bolts up.

 

Cheers,

 

G

 

My Caterham Build Diary available here

[Roadsport06]

Does the diff line up with the mounts without the prop in?

If it does then I think

1. the prop is the SV one

2. the prop isnt fully into the g'box

3. the g'box has been located too far back (I dont know if this is possible or if it isjust sideways movement of the g'box mounting)

 

I still think that this would be easier without the g'box in place. But measure the prop and confirm its the right one with CC.

 

BRG and Yellow nose VU06 XZX

 

[Johnty Lyons]

Diff's in upside down

 

jj

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[Roadsport06]

Just looked at the pics. Definately looks upside down.

I first fitted mine without putting the prop in first

 

BRG and Yellow nose VU06 XZX

 

[mav]

1st thought is what JJ says above - Diff is upside down...

[Stuart Faulds]

LOL -the diff isn't upside down, but the top photo is.

 

Neither photo is much use because it doens't show what's actually preventing it from lining up - can't see the prop in either.

[Johnty Lyons]

I agree the photos dont show enough but if bottom photo shows top diff mount [does it 🤔] then you may be right, IMHO diff should be in first with prop shaft lying in tunnell and engine gerabox not in thats the way the build manual tells it Its easier to shim like that.

 

Then the only possible reason is hes got an SV prop shaft

Again not being there is a problem photos from greater distance showing all mounts and complete diff will sort it for once and all. 😶‍🌫️

 

jj

N.I. L7C AR 🙆🏻

Membership No.3927.

 

[CharlesElliott]

How long is the propshaft?

 

Charles

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[Graham Perry]

I can't remember, but does a seven propshaft have an expansion joint alongs its length to allow for suspension travel on the original donor vehicle ? If so could this be stuck at its extended position ?

 

Alternatively could an incorrect set of engine mounts move the propshaft back this far ?

 

Edited by - Graham Perry on 26 Oct 2007 08:12:11

[gwiddicombe]

Thanks for the info so far - I think I need a call to Caterham.

 

To clarify a few points.

- The diff isn't in upside down - the long bolt goes through the diff brackets properly as far as I can tell. The first photo maybe isn't that helpful after all

- I don't think the engine mountings are incorrect, although I was wondering this myself. Certainly the exhaust comes out through the hole in the shell correctly and lines up and attaches correctly to the manifold.

- Regarding the sequencing of the build. The manual I have says (in summary) to do, front suspesion, engine and gearbox, cooling and then onto the rear diff, ensuring that the prop is in the gearbox tailhousing prior to fitting the diff. Is this not the 'normal' sequence 🤔

- The prop shaft is in the gearbox tail housing correctly. I.E., the prop shaft is flush with the gearbox tail, with no travel when I am trying to insert the other end into the diff. Acually, could this be a problem - I was actually expecting there to be some travel possible for the prop shaft.

 

One other point/question. There is a 'plate' on the diff where the prop shaft joins. This doesn't seem adjustable but looks to have 1.5-2cm clearence from the main body of the diff. Is this normal, or could my problem be something to do with this I wonder?

 

Cheers,

 

G

 

My Caterham Build Diary available here

 

Edited by - gwiddicombe on 26 Oct 2007 08:27:34

[DMT]

See here

 

You will need to scroll down a bit but the pics maybe useful.

I put mine before any of the suspension and before the engine as it was about the only bit I could fit as there were so many missing parts and even then I had to get a new diff bolt as mine was so bent!!

 

 

[gwiddicombe]

DMT - possible error in the link 🤔 It goes to the area meet page on the Lotus 7 site

 

My Caterham Build Diary available here

[DMT]

sorry here 😬

[gwiddicombe]

OK - I see from yours that you put the lower bolts in first. That is something I didn't try, so will give that a go next time I work on the car.

 

I was wondering if my top bolt may not be straight, but I did check that yesterday and it seemed okay to me.

 

My Caterham Build Diary available here

 

Edited by - gwiddicombe on 26 Oct 2007 10:00:59

[k80rum]

It might sound silly, but make sure that if you're putting in the top bolt first, you've lifted the propshaft flange on the end of the diff, over the chassis crossmember. It looks from the first picture as though it's fouling

 

Darren E

 

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[darren f]

The manual I have says (in summary) to do, front suspesion, engine and gearbox, cooling and then onto the rear diff, ensuring that the prop is in the gearbox tailhousing prior to fitting the diff. Is this not the 'normal' sequence

On my build (R300 2003), the AM said to put the diff in first, laying the prop in the tunnel but not fitting it. I wonder why the sequence has changed 🤔. Diff fitting often seems to be a nightmare- the L7 Club perceived wisdom used to be (1) fit the top bolt (2) centre up with washers and (3) machine or taper a 'lead in' on the bottom bolts to aid fitting. The top bolt was a problem on mine as the diameter was too big, resulting in no 'adjustment wiggle' (technical term 😬) and had to be returned to CC.

 

Sorry, this doesn't help solve your alignment problem, but maybe the fixing tips might help later.

[gwiddicombe]

Thanks for everyones input.

 

For info, the prop shaft I have appears to have had the wrong part number stamped on it. I measured my current prop and sent the measurements to Caterham and it turns out that it is 50mm too long.

 

Caterham are sending a replacement prop out which I'll have a go at fitting if it arrives before the weekend.

 

Cheers,

 

G

 

My Caterham Build Diary available here