Rear axle

[PaulRM]

Anyone know the variations in the rear axles and diffs during the Javelin's life? Did the axles change when the brake set up changed to fully hydraulic?
Did the diff ratio ever change? Did the casing part numbers change?

Any tips gratefully received.

[RichardMc]

Hi Paul,
There are differences but I’m not sure anyone ever got to the bottom of when / what changed. The Javelin and Jupiter axle are not the same ratio, the later Jupiter housing is slightly larger to accommodate the Le Mans 4.1 CWP which won’t fit in a standard Javelin case without modification by grinding some material away. The Javelin axle is narrower than the Jupiter one but not by much. I’m pretty sure the panhard rod is different length between a Javelin and Jupiter so there is a good chance the drive tube bracket is in a different place too. Many years ago Mike Smailes and Geoff McAuley had some axles modified to raise the final drive for the competition cars and I seem to remember that there was a difference even between two Jupiter casings they used. You can fit a Jupiter axle in a Javelin but the rear wing inner fold needs trimming back to stop the tyres rubbing, you can also put a Javelin axle in a Jupiter which lowers the final drive for sprint and hillclimb events but makes it a bit too low geared for the road, especially on 15” wheels.
I’ll be back in the workshop later this week, under the supervision of the font of all knowledge, what is it specifically you are trying to do?

[PaulRM]

HI Richard

Thanks for your input. I have an early PA javelin with I believe a Salisbury 3HA axle - so, low fd ratio, 39/8 crown wheel/pinion, and hydro mech brake set up. Mine is noisy and far too much back lash. I have since done some research by investigating the forum more thoroughly, and also finding some helpful info in the Nankivell "Jupiter, Special Body" book.

I could rebuild the axle, but internals are allegedly very rare now, and even the oil seals are not stocked by JCS. Or I could fit a later axle and weld correct brackets on it etc.. I want though to keep the hydromech set up.

Basically a member advertised a 'new' rear axle in the magazine. I was keen to see if it would be suitable for my early car without having to do a 600 mile round trip to see if it was. Pictures from the seller now show that it is different and probably from a later Javelin.

[RichardMc]

Hi Paul,
Makes sense now, I don't think I've ever seen the hydro-mech setup in the flesh. You might be lucky and find the standard Javelin CWP will fit but the oil seals might be an issue. I'll ask my dad on Friday, he has had plenty of Javelins and I think one or two may have been a PA. We have a couple of diffs kicking round in the garage but I'm sure these are all the later ones.

[PaulRM]

Thanks. It would be great to hear if he has anything suitable.

[RichardMc]

Hi Paul,
I checked today with the boss, it sounds like the early 3HA is different to the later 4HA diff that was used when they changed over to fully hydraulic. We don’t have a 3HA but the 4HA was a larger casing. However the 2.4 (MK1) Jaguar, early Volvo and Morgan used the 3HA. The owner forums suggest that the 4HA internals will fit but other people strongly disagree (as per normal on the internet). Salisbury part no. 3HA -15/23, Jaguar part no 4138 is a 4.55 CWP that fits the 3HA and there are also lower geared options. It might be worth looking at a Jaguar or Morgan spares company for parts as they both used the 3HA and generally have a larger stock of spares than JCS simply because there are more cars using this differential.
This may help:

https://www.scparts.co.uk/en/jaguar/jag ... rear-axle/

Shockingly expensive though.

[Srenner]

The factory rear axle is a 3HA aka DANA 23. Easy to tell from looking at the shape of the rear cover. 3HA is symmetrical, the 4HA is not.

There were two types of 3HA with slightly different internal dimensions. My guess is that any full hydraulic is the larger/more common axle. As a DNA 23, they were used in 6 cylinder Studebakers post-war, as well as front axles on some WW2 Jeeps, as well as the Mogs and Jags. The DANA 25 was more common on the Jeeps and quite a few parts can be swapped.

Spline counts, shaft diameters and shaft lengths are all different per each manufacturer's requirements. Oil seals can be found on sites selling the Mog, Jag or Jeep parts. I reckon there are not a lot of Studebaker sellers in the UK.

Have fun!

[PaulRM]

Many thanks everyone for your helpful feedback.

[David Morris]

Hi All,

I once had an early Javelin, with hydro-mechanical brakes, and she must have been fitted with the 3HA axle. Compared with the later axle fitted when Javelin's had full hydraulic brakes, this early axle had really 'weedy' half shafts and the car suffered from a stripped Woodruff key on one side. Compared with the later axles, everything about this early axle was weak.

The later axles at the wheel ends were really 'chunky', with everything a good 50% bigger.

I believe Jowett's bought-in the axles from Salisbury and added the brackets and fittings themselves. Good thing they didn't decide to make them themselves, like the gearboxes, as the later Salisbury axles are pretty tough and don't give many problems.

All the best,

David

[nigel jarrett]

Hi All
I think also the later axle apart from all the other noticeable differences has also got a slightly wider track putting the tyres closer to the wings

[David Morris]

Hi Nigel,

Yes, I expect you are right. The later axle also had a different Panhard rod, which was slightly longer and thicker in width, compared with the hydromechanical axle.

As a new member, who might have opted for the Severnside section, if we were still operating, do please let me know if we can help out with any Javelin spares?

All the best,

David

[Smithgrove]

I have an early hydro-mechanical Javelin with, I assume, a Salisbury 3HA axle. The pinion oil seal needs replacing as it is leaking badly. As JCS do not stock the early seals can anyone tell me what the correct leather oil seal should be. I've done an internet search that comes up with various vehicles with Salisbury Axles but not Jowett. Help will be appreciated.

[Keith Clements]

54282
Pinion Oil Seal
618
ha-019-1

54255
Hub Oil Seal Assembly (HA-057-l)
643
HA-057-1

These are the seals for the hub.
viewtopic.php?p=17369#p17369

This thread gives notes on fitting.
viewtopic.php?p=23185#p23185
Peter Pfister recently replaced the seal on his Javelin. I do not know where he sourced.

This supplier might have one.
https://coventryautocomponents.co.uk/st ... al-2HA.019


You might also consider this tool .
https://www.dingocroft.co.uk/acatalog/R ... 1_002.html

[David Morris]

Hi Smithgrove and Keith,

Unfortunately, the Jowett part numbers quoted by Keith refer to the later, full hydraulic axle and Smithgrove is, I believe , asking about the earlier axle. The later Jowett numbered parts are very unlikely to be correct. However he HA numbers also given by Keith are correct, and probably refer to Salisbury parts.

Obviously, JCS would be the first place to call, but they maybe out of stock?

Failing JCS, I would recommend going to any of the many the Landrover parts stockests, looking for axle parts from an early Series. They used Saliabury axles and may well have stock.

All the best,

David

[Keith Clements]

20240604_110418.jpg

20240604_110433.jpg

From the parts book dated May 1948

The HA numbers are correct for the 1948 axle.
In addition the axle shaft oil seal is HA-079.


Pages 49 to 54 of the June 1950 maintenance manual comprehensively cover the rear axle.

viewtopic.php?p=45909#p45909