Hi all I'm trying to figure out whats gone wrong with the steering system of a 110. Its had a replacement steering box fitted and a new hose from the pump to the steering box. When reassembled and with the engine ticking over turning the steering wheel to the lock position resulted in the new hose being blown apart by pressure. After a lot of headscratching can anyone give any suggestions as to whats gone wrong?
Britpart hose was it?
Does 'blown apart' mean a burst in the rubber hose or was an end fitting/metal tube blown off?
If the latter, it could be as simple as a badly made hose.
The hose was made up by a local hydraulic hose dealer and is alleged to have a burstiing pressure of 1600psi. The original had jubillee clips to hold it together so the normal working pressure can't be very high. The first failure was the ferruled end blew off the joint. However since posting the hose was re-jointed again with a fully crimped ferrule and tried again. This time it split the hose! What should the maximum pressure the pump develops be and is there a safety pressure relief valve built in to the pump or the steering box somewhere? All this happened with the engine ticking over not at high revs.
Yes, there is a relief valve in the pump. That could be sticky. A really heavy grade of oil could also be causing your problems.
Note to self...
PAS pumps can kick up "A Lot" of presure (1000's of PSI for a good pump and tight belt) if the valve is stuck, or re-assembled the wrong way. (No one has had the pump apart have they?...)
When it's all fixed, remember not to hold the steering on either end stop for any more than a second or two max. It's in the user manual, not only Landies, but all the cars I've had for work with PAS, it's mentioned in the handbook.
Else, you cook the oil in the pump, as it only goes round and round the pump via the relief valve, then the pump fails, and fill's the system with scrap.
A mechanic friend does quite well fixing such things on expensive shiny motors... They all suffer from it to a lesser or greater extent, related he says to the hair colour of the nut holding the steering wheel!
Why was the PAS box and hose replaced in the first place?
Blown seal due to sticky valve in the pump perhaps?
Jubilie clips on the high presure hose from pump to box are a no-no, but OK on the others. (Little to no presure.) My hybrid has PAS hoses made by a local hydraulic co'. No problems for 8 years now, except the shaft seal on the pump started to leak due to old age earlier this year. The box is leak free too.
Regards.
DaveB
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