I have a new hole

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Vanny
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I have a new hole

Post by Vanny » Sun Nov 27, 2005 8:57 pm

I have a new hole and you really wouldn't believe where it is!

So if you think you've had a long hard depressing day have a thought for me who has managed to blow up there power steering rack! And i dont mean i broke a pipe, or sprung a leak, i exploded the ram and ripped a bloody big gaping hole in the side of it!


And here is the picture!

Image


As you can see im extatically happy and while currently watching top gear, i am seriously drooling at the thought of going to the pub!






So! Anyone got a full rack? Better still anyone have even the foggiest why it exploded?

Gonna go get a Xantia rack and see if it will fit! Scrappies dont have one really and i dont fancy trying to find one in a scrap car and pull it out the bottom, the local scrap has LOADS of Xantias with the engine out, making life a bit easier! Yeah i know there different and totally different widths, but you never know!

God damn this is a labour of love!

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Post by sleepy0905 » Sun Nov 27, 2005 9:09 pm

Vanny i have a ram here you can have for a tenner for the postage. :D
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Post by jeremy » Sun Nov 27, 2005 9:24 pm

Bloody'ell - never seen that before!

Theory:

On a BX there is a pressure relief valve in the flow divider. (ball bearing under a spring under the hex socket bolt on one side). This controls the ultimate system pressure and I'm told can be used to adjust the weight of the PAS. (When I tried it for another reason it didn't seem to make much difference but then I found the thing was assembled incorrectly anyway)

You have a twin outlet pump - does it have a pressure limiting device or are Xantia rams made of better stuff? I assume they are external rather than integral with the rack as is British practice. Could you fit a xantia ram rather than the whole rack?

jeremy

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Post by ken newbold » Sun Nov 27, 2005 9:25 pm

ten out of ten for getting under there with the camera :o at least its only the ram, they're easy to change.

As for why it's blown up, you alone should have the best idea, as only you know what alterations you have made to the hydraulic system. Or is it just one of those things, must admit though, this is a new one on me. :?
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Post by Mr B » Sun Nov 27, 2005 10:26 pm

Is that Xant pump overdoing it a bit?
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Vanny
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Post by Vanny » Mon Nov 28, 2005 12:21 am

Hmm, no FD on the car, but it does have a pressure regulator (well it's internal to the bit the accumulator sphere plug into isnt it?). I thought the ball in the FD was just to prioritise which bit got what, ie make sure the brakes are the last to die? This function is carried out in the pump rather than the FD on mine which i guess makes sence?


I'm very sure the changes in the hydraulics are NOT the cause of this catastrophic failure (nice crack propagation, maybe it could be a project?). The difference in pressure is only something like 10psi between BX and Xantia pump and when i originally spoke to Pleides the impression i got was that the two PAS racks (Xantia and BX) are fundamentally identical with only really the pinion valve being slightly different, and the control arms being longer!


Just to put more perspective on the problme and a possible cause the story goes like this;

We had a leak on the rack which was quickly identified as one of the pinion to ram pipes not being tightened ( :roll: ). After sorting this we took about sorting out why it had no PAS, and assumed an air leak. As advised we tried the lock to lock procedure. It turned easily to the laft (with engine running) then turned about 20degrees back to the right and got stiff and made something of a loud hissing noise (kinda like the FD makes whent here isnt enoguh fluid). By applying pressure on the wheel to the rightit slowly turned and bacame a little easier to turn, what i would describe as an air lock clearing. it then turned easy back to the left. But it became very heavy to turn right (a lot heavier than the first time). So we got the book out and it had nothing useful to say and so with the engine off we tried again to turn to the right, solid and very much so. started her up again and still solid, but resistance grew on application of force.

Anyway here's the down falling, i let my 'friend' turn the wheel while i investigated. He decided the wheel would turn under force, so did, and it was stiff but from his description it was hard but eased (like an air lock) and so he turned it back to the left to try again. On turning to the right the second time it was initially stiff, then became easy, then the ram exploded! I was watching for drips at the time so watched the ram explode (and cried a little).


The options as i see them are;
1) there was an air leak, which cleared, but the ram was already weakened and on applying the pressure from the system it gave in.

2) the reconing of the pinion valve went some how wrong, and caused the air lock and the added force caused the ram to fail and the increasing resistance was due to the increased compression of the air.

3)The car is actually called Christine and Mr Steven King wasnt actually writing fiction on that one!



Having briefly perused the haynes, it seems confident that the rack is easy to change with the engine in the car HA HA HA HA HA Worth a shot though!


I think the best plan might be to go look for another PAS ram (will probably have to be a Xantia one!) and see if that blows up as well. Then when it fails try swapping the rack with engine in place. At the moment i cant even get the bloody thing out fo the garage!




Just as a couple of pointers;
1) suspension is rising and falling smooth as hell, i've only seen one BX as good!
2) it starts in literally 1/4 of the cycle with the new battery on it
3) the alternator seems to have sopped going on fire (again, i suspec thte new battery)
4) she sounds absolutley sweat (so i just cant give up the last remaining shred of hope!)
5)when the ram exploded, it evacuated VERY LITTLE lhm, weird!

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Post by Stewart (oily!) » Mon Nov 28, 2005 1:07 pm

Did you spend your youth breaking mirrors and shooting robins Vanny, you are one seriously unlucky dude, I have never seen that one before! The rack is not too difficult to swap with the motor in situ, you just have to dismantle it to get it out, the pipes are most fun, still your motor runs :)
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Post by jeremy » Mon Nov 28, 2005 4:32 pm

Glad to hear the rest is going OK. Is it possible just to change the ram?

I can't see how any air or anything else for that matter could increase the pressure as what the pump/regulator permit must be the maximum available.

The pressure regulator is only in the suspension/brakes circuit isn't it? I thought these pumps had a separate outlet for the steering. I think I'm going to cherish my FDV after your problems!

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Post by tom » Mon Nov 28, 2005 5:52 pm

I'm surprised to see this because I would have expected the seals to fail first. Looks like the Xantia pump is kicking out too much pressure for the rack. Think a return to an FDV may be called for.

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Post by Mr B » Mon Nov 28, 2005 7:26 pm

Looks like this BX is in line for an ASBO :roll:
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Post by sleepy0905 » Mon Nov 28, 2005 7:35 pm

what do you mean ASBO i think we should all make sure our bx`s have had all there shots incase vanny`s is contageous and keep vannys in quaretine. :wink: :lol: :lol: :lol: :lol:
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Post by DavidRutherford » Mon Nov 28, 2005 9:23 pm

I wonder if everyone is getting a bit over-technical about this.... Could it not just be the resullt of some impact damage in the past?
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Vanny
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Post by Vanny » Mon Nov 28, 2005 10:59 pm

Jon, i assume you mean pinion overhaul rather than the FDV, because there evil and i threw mine away :D (been a long weekend hasn't it, its okay i can tell ;) )


I'm very much of the opinion that the amalgamation of the systems has nothing what so ever to do with it, and also that the 'natural' pressure of the fluid also had little to no part to play. If there was such a huge build up of pressure there would have been some noticable discomfort in the HP pump and no doubt the damn thing would have stalled the engine!

Given that the rack and pinion valve where working okay up until the point where the pinion was removed, i think this is simply and oversight in the procedure and either something i've messed up or somehting a little more sinister such as air in the rack combined with brut force and ignorance, along with the pinion being in such a position to stop ANY fluid returning from the ram. The resultant force has been such that it has caused the ram to fail.

My only prblem with this theory is that it was only air that seemed to come out of the ram, and it was on full extension at the time so surely it should have been LHM filled?

As for something hitting it, there was certainly no sign of it, and it would be very difficult to hit the position it failed at, infact the crack propagation im sure would have been much smaller and much less sudden if it had a defined weak spot. I think this has been simply a sudden failure in the metal rather than damage.

Though its got me thinking if perhaps something has snapped internally? There wasn't any noticeable drips before hand and as noted surely if it was the fluid pressure then it should have blown a seal?


Gonna have to get it off and cut it up! Might take it to the lab for analysis :D

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Post by ken newbold » Mon Nov 28, 2005 11:10 pm

Been watching with interest, I suspect the pinion valve at fault. any air or fliud in the ram should escape and flow back in to the system, it seems that something has stopped this happening.
As the ram feed and return pipes go through the PV my guess is something in there is blocking its path. Causing the build up of pressure.
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