Post Number: 11
|Posted on Sunday, 29 May, 2016 - 18:17:
Dear fellow mechanical masochists, I'm currently tidying up the plethora of leaks in the PAS on my SCII. I replaced the original bottom seal on the rocking shaft with two modern dual lip seals which gives me a belt and braces approach to lubricant containment. On this topic, what is the correct lubricant for the steering box? and is it filled by removing the steering box top cover and filling to half way up the steering cam?
I know the manual says to lubricate the transfer gears with grease and then fill the transfer case with oil until it comes out the fill level port, but this compartment is physically isolated from the steering box itself by the spool valve assembly, which contains hydraulic fluid. Can someone clue me up on this please? I'm also changing all of the 55 year old hydraulic hoses which leak like colanders. I notice the HP hose from the pump contains a restrictor which was clumsily installed midway along the hose and normally sits underneath the radiator shroud. As a mechanical engineer I have always considered 5 diameters downstream to the restriction and 10 diameters downstream from a restriction to be sufficient so as to ensure no turbulence at sensitive equipment. I can see why the stepped decrease in diameter to reduce turbulence leading up to the restriction, although it is nice to do this in an accessible place. Does anyone know if this was to keep the pump on curve on the suction side or to compensate for some other issue? They minimised the risk at the pump by using a larger hose on the LP side of the pump as is normal practice. Any helpful input would be appreciated as I'm hoping to have the car registered and thoroughly tested before our Concours in July and i still have many problems to resolve!!!
Post Number: 53
|Posted on Monday, 30 May, 2016 - 21:09:
As my knowledge is limited to the earlier S Series power steering, S2 is different, however my reading of the workshop manual TSD729 on this site, pages N35 and N43 will be helpful regarding the lubrication. Shell Retinax A (now superseded) for the gears, SAE 90 gear oil for the transfer box, as you say filled to the level plug, and ATF for the steering pump.
Your question regarding the restrictor I will pass to others, only to say, where is the restrictor fitted on a "factory" hose? and duplicate that.
Sorry not to assist further.
Post Number: 1543
|Posted on Tuesday, 31 May, 2016 - 00:15:
As per the manual for lubrication.
I believe the restrictor was to try and solve judder and oscillation. The steering can wiggle backwards and forwards which is never a good look.
I'm not sure how the restrictor could be clumsily fitted. . . But I think it may be rifled inside to smooth the flow? I think late one were.
Post Number: 13
|Posted on Tuesday, 31 May, 2016 - 09:28:
Thanks David and Paul. I am replicating the location and dimension of the restrictor, but hoping to do so more elegantly than the clumsy Jerry-Rigged appearance of the factory installation that was conveniently hidden from view. I had heard about the introduction of the restrictor on Cloud IIIs to mitigate against shudder which I thought were caused by a combination of the higher pressure pump and changes to the spool valve, but it appears that the restrictor was present since Cloud II at least. Thanks for pointing out what is written on page N35 David, with:
The cam and roller assembly is lubricated together with the valves etc., under pressure from the oil pump.
Is this referring to the Steering cam? Does this mean the tapered roller bearings at the top and bottom of the rocking shaft are lubricated with hydraulic fluid also?
And yet there was what appeared to be very clean oil - not hydraulic fluid in the steering box on strip down and there is still no mention anywhere including on page N44 that I can find of the steering box lubricant other than what is written above. Can someone confirm this please?
Post Number: 9
|Posted on Tuesday, 07 June, 2016 - 02:33:
I use Penrite Steering Box Lube for the transfer case. The back seal on the steering box shaft is known to leak so the fluid you observed may be a mix of fluids. I have found the after market (green Seals do not hold up well. The Crew brass double sided seals re a lot better. It is a semi extreme pressure grease.
Post Number: 14
|Posted on Sunday, 12 June, 2016 - 09:45:
Thanks Steven for your input. I didn't appear to have any leak between the spool valve assembly and the transfer case so left that seal and the whole assembly untouched. I I couldn't get a new bottom seal of the same dimensions as the old seal so I replaced the one with two seals which were approximately half the thickness each of the original. I took along my O rings as well to the bearing supplier, and the guy gave me new ones at no charge since I bought the seals. The hydraulic hoses were $400 for all 5, but the real expense will come with the myriad of genuine spares for rubber bushes and other things. Some bits are on back order so my reassembly has come to a halt. I had removed the PAS reservoir to get better access to the hose connections, so I stripped and repainted reservior and the lid. There glassy black finish looks great. Pity the rest of the engine bay is not as pretty. Time will yield results I suppose. I need to also replace the tiny black pastiche gear lever knob. The genuine item listed at £130 is apparently No Longer Available. Flying Spares offer a cheaper after market alternative for £60, but are on back order. I ordered one but no lead time is known. If mine was complete I'd have some made from it for general distribution.