LT77 G/box prop flange different to BW35 g/box propflange ?

DamianZ28

DamianZ28

Active Member
In the final stages of finishing my conversion from BW auto to LT77 SD1 manual, fitted new UJ's to the Propshaft, went to bolt back on only to discover the bolt holes on my auto prop are different to that on the SD1 LT77 prop flange,
Only two holes lines up, :evil:
Now I was tired as it was late evening so I called it night and left the garage in a clam mood.
Now am I missing something here, in my tiredness I cant remember if I rotated the shaft flange round to see if the holes line up, but im sure I checked,

Do I need a flange from the old BW35 auto box ( I've sold it..gggrr) or do I need to drill two new holes and then carefully mig weld up the the other non fitting two?
Thoughts please, Regards Damian
 
Hi,

Mine just lined up without issue so can't say what might be different with yours, can't imagine the flange off the Auto box would fit the LT77. Is it possible not all LT77 flanges are the same?

Tim
 
Hi Tim/Simon,

Yes its the opposite holes that line up, I will have another go with a fresh mind, hope fully its as you say Tim just need to rotate it 90°

The box itself is a 2600 police spec but I cant see the prop flanges being different to a V8 spec box surely ?

Thanks for your input guys! Damian
 
Hi, the SD1 prop shaft is a CV type joint and the flange drillings are as you found equally spaced.
You need to get a flange from another LT77 application or weld up 2 of the holes first and then
re-drill as they are only half a hole out.

Colin
 
The P6B auto prop bolted straight on to the LT77 flange when I did mine, and although I couldn't be certain of the origins of that box offhand, I would have said that would be the case with all of them. I have found out (admittedly from the HBOL, so I wouldn't stake my life on it) is that the SD1 gearbox and diff flanges have different bolt patterns to prevent the prop from being fitted back to front.
 
Thanks for the tips, I wouldnt put it past BL to change the bolt patters for a certain year but then again I may have just been having an overtired brain fart moment last nite when trying to fit it :oops:

I will try again on Sunday PM if I get chance as half the other halfs birthday so she may not appreciate me disapperaring into the garage :wink:
 
Hi, yes, now I think about it Harvey is right. The only time I had the problem was when I was trying
to put a conventional prop onto an SD1 axle and had to re-drill it. Well done that man!!

Colin
 
SOmething odd there. I used my auto shaft as it was on my LT conversion with
no issues apart from a vibe from not lining up the slip joint properly, which was
self induced and easily fixed.
 
All sorted, a case of over tiredness and went back in the garage with a fresh mind and hey presto it fitted like a glove ( after rotating it until all four holes lined up :oops: )

Live and learn! thanks for all the replies though!

cheers Damian.
 
Hi Tim,

Quick question, I see you have a nice flexi stainless hose fitted between both your clutch master & slave cylinders, can you tell me where you bought it from ?

I'm going to replace my copper version as no 'flex in it and I'm sure the 3/16 diameter is too small, what end unions are they on yours? Mine is the standard Rover P6 union on the master cylinder ( I cant rember the actual thread size :oops: )and an M12 fine thread for the SD1 metric slave cylinder, I reckon I'll go for 100cms, same length as the copper pipe.

Many thanks Damian
 
Hi Damian,

I replied to your e-mail but will stick it up here as well for completeness:

Hi Damian,

I bought ours from

https://www.merlinmotorsport.co.uk/s/go ... for-3-hose

-4 hose is bigger ID but don't think there are enough union types available to make it work.

I just bought the fittings are a length of braided hose, it isn't hard to assemble yourself, I did try and find the invoice on their online system but couldn't. I think the unions where (from memory so check these make sense) a 3/8" unf conical seat one from the master cylinder end, then an M12 male to M10 male adapter (this isn't shown on their site but they have more than they list on there) then a M10 straight swivel union. You need one swiveling union so that you can tighten the hose up without winding it up!!!

Phone Merlin they are great people and will sort you out.

When I first did this I, like you, was worried about the ID of the hose etc.... as a clutch moves a lot more fluid at a much lower pressure than a brake does and I thought I'd end up with a lazy clutch action on the way up but no it's fine, the action is quick and you can very easily spin up the wheels.

This isn't the cheapest solution to the problem, unions are about £10ea and the adapter maybe £5, hose is about £1/m and I think that's pre-vat so you're looking at approx £35 by the time posted to you? Ours has been in place for nearly 4 years now and the car has been worked really hard and this part certainly hasn't caused us a moments problems :)

Hope that helps,

Tim
 
Hi Tim

Thats great information, think I'll call Merlin as it seems to be exactly what I require, may thanks for your help :D

Cheers Damian
 
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