Sp250 rear axle

[ppiantel]

The Sp250 Owners Club website states ( speaking of Specifications ), that two different back axles were used on the Sp, the early one with three plugs, and a later type of 7HA with two plugs, that was definitely better.
The Brian Long book states ( page 134 ) that the earlier one had two plugs and the later type had three plugs in the casing and this was far better in service.
Does anybody knows which is the true statement?
On another subject, is the definition of the oil capacity of the rear axle to be 0,85 liters correct, and in both cases of the axle types?

[Kbeal]

the earlier one had 3, top, centre and bottom

Kevin

[silverdart]

Sorry to disagree Kevin but, having recently rebuilt a series one axle I can confirm that this is the one with only two plugs.
The top of the axle casing has not been machined to accept a plug.

Dave.

[Vortex O'Plinth]

Sorry to disagree Dave but my late axle has two plugs. See the Club's description of the car here.

[#100910]

The parts catalog lists two diffs:

1st condition: 7HA-001-10
2nd condition: 7HA-001-30

For the 1st condition it lists "Plug for filler and drain apertures" quantity required = 3
For 2nd condition it only states that parts not itemized are the same as for the 1st condition

A kind soul has posted the Salisbury Axle Manual online, perhaps some clues there?
Page 25 shows all 7HA to have the same capacity.

http://www.thecarnut.com/Manuals/Salisb ... ervice.pdf

[DaveM]

Just overhauled a series 1 Diff it had 3 plugs
The only other differences are internal, bearings and pinion length

Have a look at my post "salisbury axle series 1 - differential" on page 3

Cheers Dave

[SPAR]

I think that it was the earlier axle that had 3 plugs for two reasons:

First, the original (red, soft cover, typewritten) Advance Service Manual shows a drawing of the axle with three plugs. Secondly, the factory subsequently issued a note to all distributors advising them to saw off the square end of the plug when the car was next serviced because it had been found to foul on the underside of the rear seat under certain vigorous driving conditions!

[daimlersteve]

Yep, three plugs early unit

[Flinty]

But which is the better of the two?

Steve.

[daimlersteve]

The Later , bigger carrier bearings and longer pinion bearing spacing .