Posted From: 188.8.131.52
|Posted on Monday, 18 August, 2003 - 11:08: |
My car Silver Wraith WGC66
The Bijur pump pedal comes up more rapidly that I think it should (10 seconds cold and 5 seconds hot). No oil is leaking out anywhere (except where it should be coming out) and I suspect internal leakage bypassing the pump piston. I see this as a developing problem rather than a complete failure because it appears that all chassis points are being oiled. At least I see wet from oil every place. However, I want to address the pump now before it gets worse.
It appears that the piston may be accessible without removing the pump from the car, but I cannot tell for sure. My service instructions are rather brief on Bijur, and pump instructions address only servicing the filter at the pump discharge. Has anyone been successful in replacing the leather piston seal while the pump in in the car? Any tips for me on how to do this task?
Post Number: 97
|Posted on Tuesday, 19 August, 2003 - 16:22: |
I recall having some information in our archives but will not be able to access this until I return home next week - will post more information around this time next week unless someone else can assist.
Posted From: 184.108.40.206
|Posted on Wednesday, 20 August, 2003 - 21:11: |
Mine takes around the same time to return, and seems to work well. The only time it returns quicker is when the reservoir is empty, and the pump is not getting any oil. I put 90 weight gear oil in mine, is this correct?
Posted From: 220.127.116.11
|Posted on Wednesday, 20 August, 2003 - 21:42: |
I think a key symptom of leakage past the piston seal is the variation in time with everything cold compared to nicely warmed up under the bonnet.
A flow rate change should not occur with a rise in underbonnet temperature because the temperature has not changed at the points where the flow restrictions are located (steering and suspension points) almost all of which receive a cooling flow of ambient air as the car is driven.
The reduction in time points to flow restriction at some place that is affected underbonnet temperature, i.e., the bijur tank.
Before I go at the pump I will test it by closing off the pump discharge, in which condition the pedal should not come up at all, and any movement in that condition indicates piston or check valve leakage.
Marty, I believe SAE 90 was the last factory recommendation around the time of the last Bijur equipped cars. One question about that, however, relates to the EP additive in virtually all current gear oils. This additive I have heard attacks brass, and many of the parts fed by the Bijur have brass wear surfaces. I have been told not to put gear oil with EP additive in the gearbox because the synchros are made of brass. However this EP thing might be another myth.
Posted From: 18.104.22.168
|Posted on Wednesday, 20 August, 2003 - 22:06: |
The times that you mention for the Bijur to run a stroke are very consistent with the time taken by the Bijur on my MkVI - and I know that it has been overhauled in the last 2,000 miles.
Does you system dribble at the appropriate points when standing in the garage? Have you tried spreading newspaper under the car and giving several strokes, and assessing the oil patch sizes? If (a) they are all there, and (b) sizes replicate from one side to the other, then I wouldn't worry - if in doubt give an extra stroke!
I agree completely about choice of oil. Here in Oz we can usually get 1- or 2-litre containers of straight SAE-90, which I use. I have been told on what I regard as good authority (but haven't sighted the actual document) that R-R issued a retrospective instruction to use the heavier oil> Don't do what saw one man do, and fill the reservoir with old sump oil ... "It'll only go on the ground, won't it?"
Posted From: 22.214.171.124
|Posted on Saturday, 23 August, 2003 - 20:42: |
I was told many years ago not to use the EP additive oil in the diff of my Austin 7 for the smae reason, it attacks the brass. Didn't think of that, will drain my tank and replace with straight 90 oil.
Post Number: 36
|Posted on Sunday, 24 August, 2003 - 13:59: |
The Factory recomended test involved blanking off the outletfrom the pump pushing the pedal and seeing if the pressure would hold. It's 500 years since I pulled a pump apart and fitted as I recall a new leather but a little ingenuity should meet the challenge.