Early 408 Differential Parts

[RJGreen]

My 408 Chassis number is 7023. Information in the resources section lists the differential in the 408 as chassis number 7201 onwards as being a 4 HA Salisbury Hypoid Rear Axle Unit. What differential was used in prior vehicles? I'm looking for bearings, seals, etc. I'm in the U.S. and would appreciate any information regarding this differential.

[Kevin H]

According to the "407 and 408 Workshop Manual (up to chassis 7200)" they also used the Salisbury 4HA rear diff

[RJGreen]

Thanks, Kevin for the information on early differentials and your prompt reply.

[PEU186F]

I recommend that you talk to Graeme at Bristol Cars Services. Salisbury made axles for a lot of vehicles including Landrovers and the bearings and seals are likely to be identical. But the seals from that era weren't as good as the modern equivalent. I learnt from Martin Barnes at ACCS (which no longer exists) that he had worked with BCS to develop a slightly undersized pinion seal to counteract the fact that the original leather seal slowly ground the pinion shaft slightly undersize. I have to say that the undersized seal worked, and continues to work, a great deal better than the standard Landrover seal that BCS had supplied to me some time prior to that collaborative effort.

[RJGreen]

Great information. Thank you. Also, I think EnglishParts.com has a pinion shaft sleeve to compensate for wear caused by the seal.

[RJGreen]

Are there any reprints available for the 407/408 Workshop Manual up to chassis 7200?

[Kevin H]

If anyone has reprints of the workshop manual available it will be the Bristol Owners Club (BOC). You may however have to join (and pay £75) to become a member to get access to reprints.

I suppose I could make a copy of mine, it's just a matter of finding the time to do it.

Is there any specific information you require?

[RJGreen]

Kevin,
I'm primarily interested in the pinion nut and axle nut torque specs. You have been very helpful and I would not ask you to make a copy of your manual. Most everything that I've encountered on my vehicle has been rather straightforward.
Thank you,
Ron

[Kevin H]

Ron,
I am happy to provide whatever information you need from the workshop manual, however it provides very little information about the rear axle - just a few paragraphs.

I have workshop manuals for the Aston Martin DB4 and DB5 which go into great details on rebuilding the differential - I suspect they also use the Salisbury 4HA diff, but I can't be sure. Despite providing pages of information about rebuilding it they don't actually say what it is!

That said, I once sheared a bolt on a DB6 diff cover because the Aston workshop manual gave an incorrect torque spec!

It's 1am here now but I will see what I can find out tomorrow.

Kevin

[Geoff Dowdle]

Ron,
The Salsbury 4HA is fitted to many British cars including Jaguar of the period ,
probably Mk VII to MkIX & Mk11
I dont have any specs on those models but the later models like Jaguar E type used a Salisbury 4HU and the torque setting for the Drive Pinion nut of the 4HU is 125ft/lb . I suggest you look for a Jaguar workshop manual or take it to a diff specialist .

Geoff

[Kevin H]

Ron,
It turns out the Aston DB4,5&6 all used the 4HA, therefore I have a detailed manual on maintaining and adjusting the differential. I scanned it and created a PDF file, you can download it via the Resources section on this site here it is titled "408 and 408Mk11 differential service bulletin"

Kevin

[RJGreen]

Kevin,
The information you forwarded is precisely the information I need. I can't thank you enough for taking the time and effort to assist me in undertaking the repair of this differential properly.
Ron

[RJGreen]

Geoff,
Thank you for your response. I think you have a valid point in referring me to these Jaguar models. It appears that the Dunlop disc brake calipers on some models of Jaguars are what has been used on the vehicle that I have.
Thanks again,
Ron

[Kevin H]

You are welcome Ron, it was easier to provide that one because I have a loose leaf copy of the Aston DB5 workshop manual that the information came from.

I have now taken the Bristol 407/408 Workshop manual apart and copied the section covering the brakes and front and rear suspension - you might find that information useful too. Again it's an external download link and it is in the Resource section of the site here

The disc brakes are the same as those used on the Mk2 Jaguar (but not the Mk1).

[RJGreen]

Kevin,
I can't thank you enough for taking the time and effort to provide me, and the forum, the information regarding the 407/408 Bristol vehicles. This has been a tremendous help to me in my efforts to make my vehicle roadworthy and safe.
Thanks again,
Ron