pressure warning light at tickover

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richjenn
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Location: devon

pressure warning light at tickover

Post by richjenn » Wed Jul 12, 2006 5:06 pm

Hi
My 1991 BXTZD estate pumps up quick as a flash, and all goes well till it warms up. After a while, the red lights come on at tickover, go out as soon as revs go over 1000rpm, and the accumulator ticks like crazy. When all has cooled, things go back to normal.
Bought a new accumulator sphere, but the old one refuses to budge! (Bah!)
Is this likely to be a cure, or is there likely to be a problem with regulator too?
I have a regulator assembly off a scrap car that could be fitted, but much more work than a sphere change - always assuming the sphere WILL come off!

Is it worth investing in a sphere removal tool?
My local mechanic says no, but I'm a bit worried that all the bashing may do some harm.
Thanks!
richard (maybe I should buy a Micra after all.........)

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Oscar
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Post by Oscar » Wed Jul 12, 2006 5:17 pm

When was the last time the system was hydraflushed? You may have dirt etc blocking the valves somewhere.

Oscar
(Red BX 1.7TZD ("Well, it is a style icon" - Tom Sheppard)) "Was", Tom, "was"

jeremy
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Post by jeremy » Wed Jul 12, 2006 5:28 pm

Sounds like the accumulator is flat - nice simple definitive test - run engine with car at normal height for a couple of minutes, turn off engine and sit in boot. Back of car should drop a long way then after about 30 seconds rise to its original height - powered by magic with a little help from the accumulator.

If it doesn't then the most likely problem is the sphere - and as you say the car rises instantly then this itself is a sure sign of a flat accumulator as there is no gas in it to compress (which takes time!)

The other possible reason is the non-return valve situated under the sphere. Over a period of time this wears its seat and even with a sound sphere can cause rapid ticking and a lack of accumulator capacity. This valve can be re-seated with the regulator in situ:

Remove sphere and find bolt securing a plate on the accumulator face on the regulator. Remove the bolt and catch the ball bearing if it falls out (which it probably will do.). Stick the ball back in its hole with a dab of grease then tap it smartly ONCE with a BRASS rod, then re-assemble.

If you tap it more than once you are at risk of making things worse by making a number of overlapping seats which won't seal. If you use a steel rod you risk putting a flat on the ball which will prevent it sealing.

The first one I did I used an old copper MIG nozzle held on to the end of a steel punch with a middle size Citroen pipe seal (tube type)! The important thing is that the contact should be brass or similar.

After re-seating the ticking time went up form about 9 seconds with a new sphere to something that I can't be bothered to measure! - Not bad for a no-cost repair.

Re-seat the valve when you do the sphere by all means but you definitely need that repair and re-seating won't be a substitute.

You can make sphere removal tools yourself. Mine is made from the remains of a chain oil filter wrench that i broke trying to remove a sphere! I took the hex bar through which the chain was threaded (and which has a handy 1/2 inch socket in it) and welded a length of 1.5mm sheet steel (width the same same the length of the hex bar) to one side. I then wrapped the sheet round a sphere with the hex bar attached so i could measure how much steel was needed to weld to the opposite side of the hex bar. Cut and weld.

The idea is so that when the bar is rotated anti-clockwise it wraps the steel band tighter so that it grips the sphere - harder you pull - tighter it grips! (looked at from the top with the hex bar near you and the sphere touching it but away from you 1st weld is between bar and sphere with the steel band running to the right and round the sphere and returning to be welded to the flat on the bar which is nearest to you).

I made this tool to remove the rears from by BX Estate - which looked ancient. It took me far longer to get the car supported and the tool in place that it did to loosen them! (I did use an 18 inch breaker bar and pushed with my feet with my body outside the perimeter of the car!)