Due to being temporarily out of action for the next couple of months I was telling my neighbour that I would have to delay the changing of the brake fluid on my Vectra.
No problem he says I'll do it for you.
He is a vehicle mechanic by the way.
What I'll do he says is connect my compressor air line to it and blow all the old fluid out through the nipples. Refill and bleed off again.
"Thats great I said" However afterwards I thought I've never heard of it being done this way and began thinking could the compressed air cause any problems to the ABS or if it could turn seals over in the wheel cylinders or elsewhere.
Is this the way its done in commercial garages atc.
Please advise.
Alvin
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Alvin
What your neighbour/you describe is a slightly scrambled version of the use of a pressure bleeder. Basically this consists of a fluid filled bag acted on in a cylinder by regulated air pressure. The machine is attached to the master cylinder resevoir and a valve can be altered on the machine to push fluid or compressed air into the system. It is a simple matter then of opening bleed nipples at the wheels to allow the old fluid to be pushed out by the new.
I don't like the idea of pushing air into the system so I suck out as much fluid as I can first from the resevoir, top up with fresh fluid and then blow just fluid in when I use one. Pressure bleeding is common practice these days.
Regards
Don Cox
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Thanks Don,
I don't know if my friend was describing the detailed method which you have laid out above.
He did say that he would be borrowing something from his mate and using his own air line so it may just be that I wasn't paying enough attention to what he was telling me.
I had already began thinking of how he would be doing it and was imagining him disconnecting below the resovoir and shoving HP air down the line and opening up the nipples one at a time which alarmed me somewhat.
I will tactfully ask him just what method he is using.
He is an experienced mechanic with a very large haulage company so I imagine that he knows his trade and its me who is being a pedantic witterer.
(If there is such a species.)
Mind you I must tell you about a job I was given a couple of decades ago on a hydro Pneumatic piece of laundry equipment where due to constant failures the manufacturers prescribed all oil to be removed from the system due to contamination. Myself and my mate decided that we should use a HP line to remove it all. Disaster.......
We then spent an entire weekend removing all the shuttle valves and fitting new seals to them which the HP air had turned over.
Alvin
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It certainly beats the old favourite.....
"OK Guy - pump the pedal"
"OK - now push to the floor"
This starts to get boring after the first caliper and you end up with your right leg looking like that of the loose-head prop from Newport RFC.
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Presumably all you are describing is a professional version of the Gunson's Eezi Bleed which uses pressure from the spare tyre via a brake fluid reservoir connected to the vehicles own reservoir to do the same job. Got one sitting on the garage shelf and its certainly better than the "OK now pump....." method which must have caused more marital barneys over the years than enough.
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Eezi Bleed gets my budget vote. I'm sure this guy knows what he's doing but wise to make sure he hasn't some "clever" way of pressure bleeding at 100psi.
As you all say, the old method.......
...."OK you can let the pedal up now....I already have.....wait a second and I'll ask you to put it down again....I thought that's what you wanted, it's down already now".....!!!!!!!
David
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