Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: terry paget on 07 December 2014, 22:21:16
-
I note Haynes has a bleeding order for Omegas. Does this matter when merely changing fluid, or can I do it in any order?
-
It does matter,all cars have a pattern to bleed the brakes,usally start at furthest away from master cylinder and finishing at the nearest.
-
Officially the ABS unit needs to run to carry out a complete fluid change...
For the £35 or so that most places charge to carry out a brake fluid change, is it worth the bother of diy :-\
-
My MOT shop wonders why I change it at all, I reply that Vauxhall recommends it, that brake fluid is hygroscopic and attracts atmospheric water vapour, causing corrosion of ABS components and risk of boiling under heavy use. The lads there give me funny looks, say it i rubbish.
I appreciate to chase air out of a spongy system I should bleed brakes in the right order. For a fluid change it is simpler to jack up one side of the car, Eezibleed blow all the fluid of front left, then refill and bleed front left, then bleed back left of about 200 cc's, then replace LH wheels, drop jack, jack up RHS and pump 200cc's through RH front and rear.
I am nervous of garages, they may skimp the job, also they are incline to overtighten things, like the oil filter on my sister's Meriva. Bleed nipples are easily overtightened, then break off next time round. If I do it myself, I know I can undo the brake nipples if I need to.
-
I agree. No real need to observe any order when changing the fluid. :y
Despite what your MOT place says, it's worth keeping on top of changing it as it keeps other parts of the system from degrading when the fluid is in good condition. An Easybleed is very helpful when changing fluid.
-
My MOT shop wonders why I change it at all, I reply that Vauxhall recommends it, that brake fluid is hygroscopic and attracts atmospheric water vapour, causing corrosion of ABS components and risk of boiling under heavy use. The lads there give me funny looks, say it i rubbish.
I appreciate to chase air out of a spongy system I should bleed brakes in the right order. For a fluid change it is simpler to jack up one side of the car, Eezibleed blow all the fluid of front left, then refill and bleed front left, then bleed back left of about 200 cc's, then replace LH wheels, drop jack, jack up RHS and pump 200cc's through RH front and rear.
I am nervous of garages, they may skimp the job, also they are incline to overtighten things, like the oil filter on my sister's Meriva. Bleed nipples are easily overtightened, then break off next time round. If I do it myself, I know I can undo the brake nipples if I need to.
If ever anyone wonders why garages are untrustworthy, this should convince them. >:(
-
I'm, as most know on her that've been following my ''The' Omega Progress Diary' I'm resurrecting a poorly old lady from the dead... that's including full suspension replacement, new battery, new leads, full service, all fluids, cambelt, the lot, even sourced decent replacement fuel tank straps :)
On asking if my mate/mechanic who knows Omegas better than most (been servicing/repairs all the taxis in the local area since Carlton/Senny days) he asked "Well.. I don't know why you're bothering with all this, it's just an old car" :( :( :'(
Look after her, and she'll look after you, that's what I say.
-
Change the fluid. Don't worry about the order, end of :y
-
Begin at the corner furthest from the driver and proceed in order toward the driver. (Right rear, left rear, right front, left front.) While the actual sequence is not critical to the bleed performance it is easy to remember the sequence as the farthest to the closest. This will also allow the system to be bled in such a way as to minimize the amount of potential cross-contamination between the new and old fluid.
From a DIY site. :y
-
On the subject of brakes, what is there any indication of air in the ABS, other than not working? :-\
-
Begin at the corner furthest from the driver and proceed in order toward the driver. (Right rear, left rear, right front, left front.) While the actual sequence is not critical to the bleed performance it is easy to remember the sequence as the farthest to the closest. This will also allow the system to be bled in such a way as to minimize the amount of potential cross-contamination between the new and old fluid.
From a DIY site. :y
That's the way my old man taught me to do it :y
-
IIRC Haynes gives two options for bleeding sequence depending on the car's age :-\
-
IIRC Haynes gives two options for bleeding sequence depending on the car's age :-\
He says pre-1998 three channel ABS, post 1998 four channel ABS, quite different sequences.
-
On the subject of brakes, what is there any indication of air in the ABS, other than not working? :-\
Just a spongy pedal, just the same as with air anywhere else. I believe the issue with the ABS block is that, if you've done a really good job of getting air into it, you need to operate the valves to bleed it through.
There is also a circuit within the abs block that will retain old fluid, but that will soon get diluted by the new fluid when the pump operates.
-
On the subject of brakes, what is there any indication of air in the ABS, other than not working? :-\
Just a spongy pedal, just the same as with air anywhere else. I believe the issue with the ABS block is that, if you've done a really good job of getting air into it, you need to operate the valves to bleed it through.
There is also a circuit within the abs block that will retain old fluid, but that will soon get diluted by the new fluid when the pump operates.
Presumably using the expensive pressure kit? I'm wondering whether there may be some in the Elite's ABS, as the main system has been bled well. :-\
-
Hmmm, anyone correct me, but I have a feeling the idea if to find some wet grass / empty car park after it's rained, wherever, and activate the ABS (ie: brake dead 'ard) - this should pump round the little bit of extra fluid / air in the system and basically 'bleed' the ABS unit. But that's just appeared as a spark form the dark recesses of my mind, I could be wrong/imagined it :D
-
Presumably using the expensive pressure kit? I'm wondering whether there may be some in the Elite's ABS, as the main system has been bled well. :-\
No, you just need to exercise the ABS ECU using a Tech 2 while bleeding normally. It's unusual for it to be required, though, especially if the system hasn't been disturbed upstream of the ABS block.
-
Presumably using the expensive pressure kit? I'm wondering whether there may be some in the Elite's ABS, as the main system has been bled well. :-\
No, you just need to exercise the ABS ECU using a Tech 2 while bleeding normally. It's unusual for it to be required, though, especially if the system hasn't been disturbed upstream of the ABS block.
Thanks Kevin.
-
Begin at the corner furthest from the driver and proceed in order toward the driver. (Right rear, left rear, right front, left front.) While the actual sequence is not critical to the bleed performance it is easy to remember the sequence as the farthest to the closest. This will also allow the system to be bled in such a way as to minimize the amount of potential cross-contamination between the new and old fluid.
From a DIY site. :y
I accept slight cross contamination. It's not as bad as a garage oil change, which at best drains cold oil through sump plug hole for five minutes, at worst sucks oil out through the dip stick hole.
-
... at worst sucks oil out through the dip stick hole.
Not all cars have a sump drain plug ...... hence you HAVE to use an oil sucker outerer :y :y
-
Not all cars have a sump drain plug ...... hence you HAVE to use an oil sucker outerer :y :y
Sump drops will be commonplace then?
-
Not all cars have a sump drain plug ...... hence you HAVE to use an oil sucker outerer :y :y
Sump drops will be commonplace then?
If you like ..... but it'd be a lot easier/less messy with a Pela oil sucker outerer ;)
-
Personally, while its good to get new fluid through the system, I've never noticed any improvement in bleeding any more than enough through to clear the heat affected fluid around the caliper, which obviously means doing so with the caliper piston FULLY retracted into the caliper.
It is not possible for the fluid to take in moisture while it's in a sealed sysyem. Certainly one thats well bled and used with no air pockets on an old car like the omega. If there was air in the system for some time, then yes bleed thoroughly. But generally, for a correctly working system, insuring the caliper piston is fully retracted and bleeding normally is ample.
Certainly no need for tech 2, unless there has been a right royal OPPS up. Although failing to keep the master cylinder topped/while bleeding the master cylinder dry so the inlet sucks air would do it.
-
Personally, while its good to get new fluid through the system, I've never noticed any improvement in bleeding any more than enough through to clear the heat affected fluid around the caliper, which obviously means doing so with the caliper piston FULLY retracted into the caliper.
It is not possible for the fluid to take in moisture while it's in a sealed sysyem. Certainly one thats well bled and used with no air pockets on an old car like the omega. If there was air in the system for some time, then yes bleed thoroughly. But generally, for a correctly working system, insuring the caliper piston is fully retracted and bleeding normally is ample.
Certainly no need for tech 2, unless there has been a right royal OPPS up. Although failing to keep the master cylinder topped/while bleeding the master cylinder dry so the inlet sucks air would do it.
Good advice. Like checking the fuses or battery first, it's obvious - but we've all done it, it's so simple that you forget. Well, I say "we've all done it"... what I mean is I have! :y :y
-
It is not possible for the fluid to take in moisture while it's in a sealed sysyem.
.. except in the reservoir which is open to the atmosphere, of course. What I tend to do when servicing any of the brakes is to first empty the reservoir with an oil extractor, refill it with fresh, drain old fluid from each caliper while retracting the cylinder, then bleed a little through each with an easy bleed on reassembly. Do this every time you replace the pads and that's all you need to do, IMHO.
-
no more than the air gap in the sealed bottle that's been on the shelf since manufacture.
And if the the master cylinder is open then it's not sealed. ;)
-
But how do you know they don't nitrogen purge the bottles when sealing them, Chris ;)
-
it seems like we're wandering into the realms of it not being worth changing the fluid, now... :-\ personally I'll be changing mine, but it would be great to find a kind of litmus test or something to actually determine how much H20 is in brake fluid after eg: 5 years.
-
But how do you know they don't nitrogen purge the bottles when sealing them, Chris ;)
Exactly. And the bottle doesn't have a vent in the top to allow air in to displace fluid as the level drops. The amount of black crud in the bottom of the reservoir on cars where this has been neglected is witness enough to the fact that the fluid in the reservoir does degrade faster than anywhere else in the system.
it seems like we're wandering into the realms of it not being worth changing the fluid, now... :-\ personally I'll be changing mine, but it would be great to find a kind of litmus test or something to actually determine how much H20 is in brake fluid after eg: 5 years.
5years! :o Enough. As has been discussed, you don't necessarily need to change it as a separate operation, but, each time you replace the pads, release the old fluid from the caliper as you wind it back and bleed a little fresh through. That's all you really need to do, IMHO, and it only adds a few minutes to a pad change, especially if you have an easibleed.
-
Reminds me I really should do that on the M3 after I cooked the brakes at Donnington and ended up with zero stopping power :-X
-
Jeez. The point is, you don't ordinarily need tech 2 to bleed the brakes. Christ almighty ;D
I though 4 years was the service schedule for brake fluid. (No tech 2 required, unless there's a problem )
-
But how do you know they don't nitrogen purge the bottles when sealing them, Chris ;)
Correct - nitrogen purge normal for hygroscopic products ;)
-
But how do you know they don't nitrogen purge the bottles when sealing them, Chris ;)
They do.
Plus even if it was air its a very small controlled amount and not 4 years of air circulated through the vent of a master cylinder reservoir.
Also remember that as your pads wear, more and more fluid gets pulled into the system via the lines from the reservoir. :y
-
I thought the service interval for brake fluid was 2 years?
-
Oh we're not interested in all that helpfull stuff TB. Nooooo ;D
-
Lol it is two years I believe. For most cars also I think.
As for cross contamination if fluid. . .
I empty the reservoir with a turkey baster and then stick in new fluid. Then to round and bleed. I never worry about the order. When it's coming out clean. . It's done. End of IMO. You're not going to stop the old fluid from meeting the new unless you siphoned it all and refilled a totally empty system with new and then bled it of air. . . Which you were trying to avoid doing in the first place lol
Just my opinion.
-
Oh we're not interested in all that helpfull stuff TB. Nooooo ;D
Well, I could say I had to use a Tech2 to bleed tractor's brakes when I first got it... ...but not due to air in ABS.
Happy now?
-
Actually, MDTM and I had to use a tech2 at one of the recent-ish meets as well, now you mention it. That was due to air in ABS.
;D
-
I was hoping to here about popping a piston out of a caliper on rusty. ;D
Wasn't sure it was actually needed on that occasion either, but as it was available....
-
I was hoping to here about popping a piston out of a caliper on rusty. ;D
Wasn't sure it was actually needed on that occasion either, but as it was available....
In that scenario, it is handy to check there is no air trapped in some corner of the calliper. Esp as it was available.
-
Couldn't do any harm, as it was indeed available.
(It wasn't needed though :y )