| Author | Message | ||
     Alistair Riddell Experienced User Username: ariddell Post Number: 21 Registered: 1-2013 |
Hi all, Puzzling problem is currently getting in the way of forward progress on the restoration of GCH14762, by way of the power steering currently confounding me with what appears to be significant air getting into the system. When attempting to bleed the system there is a lot of bubbling coming back up to the reservoir but the fluid level does not drop. At times it has ended up climbing suggesting air is coming in and getting trapped somewhere below. With the engine running (it has only been run very briefly as I don't want to damage the pump) there is extensive foaming and the fluid level rising rapidly. Now I'd be expecting where air is getting in for there also to be visible fluid getting back out, but this does not appear to be the case here. I've had the pump reconditioned, replaced the o-ring on the high pressure hose and have replaced all of the low pressure hose run to and from the cooler. I have also tried totally bypassing the cooler and running a direct hose but the issue persists. Any advice on where I should be looking/further things to try to narrow down the issue? Regards, Al | ||
| Omar M. Shams Grand Master Username: omar Post Number: 373 Registered: 4-2009 |
Dear Al, First of all, we need to know how long you have run the system since the rebuild of the pump. When you installed the pump naturally there is air in the system that will have to self bleed. There will be bubbles forming as the air returns to the reservoir. Eventually all air will escape back and there will be no foaming at all. At that point you take the steering wheel to both locks and back several times to ensure all air is out of the system. If you have already done that, then I would look only between the reservoir and the pump. If the reservoir has no cracks and the pipe leading to the pump from the reservoir has no faults, I would tear down the pump again. Sounds to me that your pump may be sucking air with oil | ||
| Alistair Riddell Experienced User Username: ariddell Post Number: 22 Registered: 1-2013 |
Thanks Omar, The system has not been run (as in by way of the engine running) for long at all, probably 30 seconds to a minute or so at most as I was very concerned about potential damage to the pump. With the engine off the steering has been rotated many times to attempt to bleed air out, but it does seem more is being sucked in somewhere. When the car is started the noise from the power steering pump in distress is considerable (as it was before it was sent away to be rebuilt) and the foaming and bubbling of the fluid is instant and dramatic. I would expect to be getting bubbling coming out when the system bleeds, but the fact that the fluid level does not drop in line with the air escaping is the bit that concerns me, and with the level actually increasing it suggests more air is being drawn in forcing fluid out. The pump and reservoir are both visually ok, but hopefully that is indeed where the issue lies as I do not relish the prospect of trying to remove the steering rack should the problem be there! Is there a method I could use to test the power steering pump on the bench without disassembly? I didn't rebuild it previously myself and disassembly would void the warranty but it does raise the troubling concern as to if the company I engaged to rebuild it actually did anything beyond repainting the outside of it and printing me an invoice... Thanks, Al | ||
| Stefan Morley Grand Master Username: myupctoys Post Number: 376 Registered: 7-2009 |
Hi Alistair, Just a thought. Do you have the wheels on the ground ? Whenever I've replaced a rack on any car I've always bled the rack with the front wheels off the ground. Wondering if a totally empty system and the load on the rack, air could might only bleeding slowly given the back pressure from the air in the system. Would account for the foaming, and the apparent rising of the level. Guess it would bleed eventually but how much wear in the meantime. Stefan | ||
| Alistair Riddell Experienced User Username: ariddell Post Number: 23 Registered: 1-2013 |
Hi Stefan, The wheels are very much in the air, I've had this car up on stands since March and hoping to get it back on the ground shortly. Hopefully sorting out the steering issue is one of the last to be dealt with before I can do so. Thanks, Al | ||
| Stefan Morley Grand Master Username: myupctoys Post Number: 377 Registered: 7-2009 |
Alistair, Did my Bentley rack about four years ago. Seem to remember that did foam quite a bit but it subsided quickly enough after a few lock to lock movements. Can't remember exactly how long it took, but not so long as to be memorable. Guess you must have another issue. Only other thing I can think of is get the rack to move to its extremes. Not sure if it's the pump or the rack but at extremes there is pressure relief, guess that would also releive air more quickly. Still got to wonder why the air isn't being purged. Stefan | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2909 Registered: 4-2003 |
To bleed the system finally the wheels need to be on the ground to provide load. I have done rack repairs on several SZ cars. Each time I have simply filled the reservoir, run the engine for about 20 seconds topping it up while running, then lock-to-lock (under load) three or four times. After another topup that is almost that, although a final topup after a run around the block may be needed. The process always took about two minutes until almost all the air was purged. The strawberry milkshake appearance of the fluid should disappear after a short while once stopped. I dare say that if done with the wheels off the ground the process could take quite a long time and lots of waiting as there is no pressure in the system until the rack is loaded. RT. | ||
| Alistair Riddell Experienced User Username: ariddell Post Number: 24 Registered: 1-2013 |
Thanks all, RT, I must admit I was put off running the car for long given the noise the pump was making. Would it be expected to be significantly noisy for any great duration once started or should this subside within seconds? I can pretty easily drop the car back onto its wheels and enlist the help of an assistant to man the ignition key should anything go horribly wrong. This would allow me to monitor the fluid reservoir more closely and top up accordingly if it's a possibility to make the difference to successful bleeding. Is there much likelihood of damaging the pump, given I know there is fluid in the reservoir and the system is definitely not being run completely dry is there significant risk of this dropping it back to the ground for a further crack at bleeding? Rgds, Al | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2910 Registered: 4-2003 |
Alistair, I would expect the pump to become quiet with about 30 seconds once loaded. However, it would not surprise me were it noisy for quite a while before load is applied. There is a largish quantity of air to purge inside the steering rack tube, and sure at first it will raise the fluid level as it escapes. The noise, if everything is in good shape, is made by the vanes rattling due to the air and to doing no work, and loading them by raising the system pressure (turning the steering under load) should stop that, instantly I would hope, provided the reservoir is not dry. Once the steering has been turned lock-to-lock with enough fluid in the reservoir and with a load most of the air should have been purged from both fluid chambers in the rack tube. So far, I am not surprised at what you describe. So, I would suggest that trying this out for up to a minute should be safe. If the noise does not reduce markedly then a rethink is probably required. RT. | ||
| Alistair Riddell Experienced User Username: ariddell Post Number: 25 Registered: 1-2013 |
Thanks once again, the advice and guidance is greatly appreciated. I'll crack on with other jobs for the moment with a view to hopefully getting the car down onto solid ground over the weekend to have a go with the system under load. Just the rear anti roll bar to re-attach, brakes to bleed, handbrake cables to re-attach, exhaust to go back on, quite a lot of bolts to double check for torque, some fuel line to replace, and we should be good to reunite "Big Red" with its wheels once more. Dead easy, should be done in a jiffy!..  Rgds, Al | ||
| Mark Herbstreit Prolific User Username: mark_herbstreit Post Number: 110 Registered: 5-2005 |
A few years ago my neighbor was trying to bleed the power steering on his Shadow II. Whilst standing beside the car so he could peer into the reservoir whilst rocking the steering from lock to lock with his arm through the drivers window he managed to flick the gear lever into reverse. The car pinned him against the carport pillar with the result being a badly damaged drivers door with human imprint and a few stitches to his right ear. It could have been a lot worse and a timely reminder of how easy it is to do. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 374 Registered: 4-2009 |
Mark makes a good point. Only three months ago the RTA tester was testing my Turbo RL and he did the steering wobble from side to side from outside the car through the window and flicked the gear lever from N to D. The car drove itself off the ramp and crashed into a parked car. 2 months of repairs later and I no longer have the same love for the car. I have now advertised the car for sale - I just don't want it any more. Dubai Dealer Listing Moderator's Comment: Omar, I have edited your post to stop a problem with your link forcing an increase in the page width and making scrolling across the page necessary when reading this thread. Regards David | ||
| David Gore Moderator Username: david_gore Post Number: 1339 Registered: 4-2003 |
Re the problem with accidental activation of the gear selector - the Shadow workshop manual includes a direction to remove the gear shift selector thermal cut-out from the fuse board before any work on the car requiring the engine running; I presume this would also apply to the later models. I too have taken the "short-cut to bank account depletion" by not removing the relay and then inadvertently knocking the gear selector out of Park whilst checking some minor adjustments. No personal injury; just a badly damaged outer door skin from hitting the corner of a brick retaining wall to be repaired and repainted and a decision to always remove the cut-out in future when working on a R-R/B with the engine running. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 2911 Registered: 4-2003 |
Omar, Does the beach come with the car ?  | ||
| Alistair Riddell Experienced User Username: ariddell Post Number: 26 Registered: 1-2013 |
Well, that certainly appears to have done the trick. Had a fairly full on day of work on the car on Saturday (missed a nice sunny day under a not so sunny old Bentley, but hey! ) and got it off the stands and back down onto its wheels. The noise when re-attempting the bleeding was very noticeably different with load on the rack with the fluid in the reservoir being sucked down very quickly once started up. A good 45 seconds of steady bubbling proceeded as I topped off the level but with the fluid being drawn down this time. Further bubbling when moving the steering back and forth (with assistant under incredibly strict instructions not to knock the shifter) and all seemed to have settled, right up until the point the engine was switched off at which point the fluid level jumped up almost to the top of the reservoir. Upon a restart and getting Big Red out into the daylight for the first time since March and a slow drive up and down the driveway into the street the give the steering a few passes back and forth the level is now holding steady and right where it should be with no steering noise evident. Alas I didn't have a surfboard to hand to mount on the roof (the previous owner must have neglected to tick this options box along with the picnic tables or cocktail cabinet), but I did get a shot of Red basking in the sunlight for the first time in a while having been liberated of the thick coating of dust and grease it had accumulated - although I did make sure it was done out of sight of Big Green 25755 lest it get jealous of the attention. Cheers, Al  | ||
| richard george yeaman Prolific User Username: richyrich Post Number: 115 Registered: 4-2012 |
Hi Al. Must say Big Red looks the part, looks like good vibrations all the way Happy Motoring!!!! Richard. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 375 Registered: 4-2009 |
Naturally, there will have to be a suitable repost from the Dubai contingent to the Aussie one eh Richard???...... How about we start a "show me yours and I will show you mine" thread?   | ||
| richard george yeaman Prolific User Username: richyrich Post Number: 116 Registered: 4-2012 |
Hi Omar Yes I will open one in the general discussion section. Cheers Richard. | ||
| richard george yeaman Prolific User Username: richyrich Post Number: 144 Registered: 4-2012 |
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| richard george yeaman Prolific User Username: richyrich Post Number: 145 Registered: 4-2012 |
Hi Omar and all, The car in the picture above is SRH 19529 first regd Oct 1974, I still cant do pictures so the Gentleman that was doing some work on my Web page added this one for me it was taken at a Wedding on the 14.07.2012 and as you can see it was a beautiful day with not much sand about. Richard. |
