WIP: Brake bleed not going well at all
#41
12-16-2009, 08:42 PM
A lot of what I do for a living is reverse code engineering. Given that I have my hands on the LR dealer software to engineer a free version for laptops. I can tell you that all the bleed procedure does is cycle the modulator pump for a few seconds. Nothing magical about that, you can run the pump on 12V with a jumper.
It's the separate plug on the side of the module, fed from the ABS pump relay pin #87.
It's the separate plug on the side of the module, fed from the ABS pump relay pin #87.
When you're ready, let me know; I'm tracking the various Linux Carputer projects.
And I wouldn't in fact have thought running that motor was actually enough; I assume you'd have to cycle the 8 solenoid valves in the valve body as well. No?
Sure would be nice if we could get a wiring and fluid-flow diagram for that modulator. If I can get my replacement successfully bled, I'm probably going to tear my old one down the the ground and create such a document.
#42
12-16-2009, 08:57 PM
Shhhh.. .the DMCA police will get you. :-)
When you're ready, let me know; I'm tracking the various Linux Carputer projects.
And I wouldn't in fact have thought running that motor was actually enough; I assume you'd have to cycle the 8 solenoid valves in the valve body as well. No?
Sure would be nice if we could get a wiring and fluid-flow diagram for that modulator. If I can get my replacement successfully bled, I'm probably going to tear my old one down the the ground and create such a document.
When you're ready, let me know; I'm tracking the various Linux Carputer projects.
And I wouldn't in fact have thought running that motor was actually enough; I assume you'd have to cycle the 8 solenoid valves in the valve body as well. No?
Sure would be nice if we could get a wiring and fluid-flow diagram for that modulator. If I can get my replacement successfully bled, I'm probably going to tear my old one down the the ground and create such a document.
#43
12-16-2009, 09:14 PM
#44
12-24-2009, 01:22 PM
An update:
I got the replacement WABCO in, and swapping it really wasn't all that difficult, though while you can get it *out* single handed, getting it in semi-requires someone else to pull the one wheel pipe back outta your way. And *don't* drop the rubber baby buggy bumpers (though, if you do, it went down under the brake booster :-).
Final tip: lay a couple layers of shop towel under where you're going to put it back down to; it makes swabbing up any spilled brake fluid a lot easier.
So, of course, that wasn't enough to fix the problem. <sigh>
And at that point, I gave up and shipped it to my local general mechanic... who promptly diagnosed a bad master.
Through the kind offices of Paul Grant, from the forum here, I got a new one overnighted, and he tells me it's bleeding through nicely; I expect to go pick it up in an hour or two.
Moral: when you run out of problems which can be adequately explained by the symptoms you have.... consider whether you might have more than one problem interacting.
I got the replacement WABCO in, and swapping it really wasn't all that difficult, though while you can get it *out* single handed, getting it in semi-requires someone else to pull the one wheel pipe back outta your way. And *don't* drop the rubber baby buggy bumpers (though, if you do, it went down under the brake booster :-).
Final tip: lay a couple layers of shop towel under where you're going to put it back down to; it makes swabbing up any spilled brake fluid a lot easier.
So, of course, that wasn't enough to fix the problem. <sigh>
And at that point, I gave up and shipped it to my local general mechanic... who promptly diagnosed a bad master.
Through the kind offices of Paul Grant, from the forum here, I got a new one overnighted, and he tells me it's bleeding through nicely; I expect to go pick it up in an hour or two.
Moral: when you run out of problems which can be adequately explained by the symptoms you have.... consider whether you might have more than one problem interacting.
#45
12-24-2009, 07:40 PM
And I've picked it up, and it's not perfect, but it's 3 orders of magnitude better. And if I tap the pedal once right before braking, 4 orders of magnitude.
(Is that "some air left somewhere"? Or "leaky vacuum booster or hose"? Once I tap, each subsequent push until I completely let off is identical, and near-perfect. If anything, *too* good.)
(Is that "some air left somewhere"? Or "leaky vacuum booster or hose"? Once I tap, each subsequent push until I completely let off is identical, and near-perfect. If anything, *too* good.)
#46
09-04-2010, 06:04 PM
Drifting
Join Date: May 2010
Location: South Florida
Posts: 25
Likes: 0
Received 0 Likes
on
0 Posts
> THIS IS ALL SO UNFORTUNATE.
So was my brake system condition before I started.
> You should have asked us what to do next before you opened up the lines to your pump. That just made it worse i think.
> 1. How was your pump working before?
No way to tell; I didn't have enough brakes to trigger ABS.
> 2. Did TC/HDC/ABS work properly?
See immediately above. :-)
> 3. Did you have any ABS code? What were they?
No, I didn't have any ABS codes or lights either of the times I had codes pulled, as noted earlier in the thread.
> SO... I stopped using the hawkeye.... manually bled the brakes... and then...
When you manually bled the brakes, *did you get fluid at the wheel hoses, in exactly the same way that I never have? :-)
> VROOOOOM... The pump came on using the hawkeye. Then I continued using the hawkeye to actuate the internal valves and then I manually bled them
> It's almost like the pump did not run since there wasn't enough brake fluid inside it.
Could be.
No one seems to have an authoritative answer here, though, to whether the Hummer gent's assertion -- that an open pin-6-9 resistance measurement means something's broke -- is actually correct.
> I have manually bled a couple of DII's and they all have had spongy brakes, including mine. After the bleeds it was a tad better but not by much. However, on my last bleed on my rig after I used the hawkeye/manual bleed, I noticed it stops MUCH MUCH better now... to the point I can put off buying brakes for a while...
Well, my tire shop tells me that my brake pads are just fine -- and as badly as it was stopping, I guess I'm not surprised. I've always been conservative on that front anyway; I'm used to driving cars with crappy brakes. But a good emergency stop now and then is nice.
> So I agree the hawkeye or similar is a good idea.
And as soon as I'm sure I have a working modulator, I'll head in that direction, one way or another.
But I'm still trying to nail that down beyond doubt. And it seems amazingly hard to get a straight answer to that; no one seems to know for certain, and everyone disagrees...
So was my brake system condition before I started.
> You should have asked us what to do next before you opened up the lines to your pump. That just made it worse i think.
> 1. How was your pump working before?
No way to tell; I didn't have enough brakes to trigger ABS.
> 2. Did TC/HDC/ABS work properly?
See immediately above. :-)
> 3. Did you have any ABS code? What were they?
No, I didn't have any ABS codes or lights either of the times I had codes pulled, as noted earlier in the thread.
> SO... I stopped using the hawkeye.... manually bled the brakes... and then...
When you manually bled the brakes, *did you get fluid at the wheel hoses, in exactly the same way that I never have? :-)
> VROOOOOM... The pump came on using the hawkeye. Then I continued using the hawkeye to actuate the internal valves and then I manually bled them
> It's almost like the pump did not run since there wasn't enough brake fluid inside it.
Could be.
No one seems to have an authoritative answer here, though, to whether the Hummer gent's assertion -- that an open pin-6-9 resistance measurement means something's broke -- is actually correct.
> I have manually bled a couple of DII's and they all have had spongy brakes, including mine. After the bleeds it was a tad better but not by much. However, on my last bleed on my rig after I used the hawkeye/manual bleed, I noticed it stops MUCH MUCH better now... to the point I can put off buying brakes for a while...
Well, my tire shop tells me that my brake pads are just fine -- and as badly as it was stopping, I guess I'm not surprised. I've always been conservative on that front anyway; I'm used to driving cars with crappy brakes. But a good emergency stop now and then is nice.
> So I agree the hawkeye or similar is a good idea.
And as soon as I'm sure I have a working modulator, I'll head in that direction, one way or another.
But I'm still trying to nail that down beyond doubt. And it seems amazingly hard to get a straight answer to that; no one seems to know for certain, and everyone disagrees...
I just replaced valve switch unit and cleaned out modulator pins (this was a flood DII). I also own a Hawkeye, exactly how do you use it to bleed brakes?
From the ABS circuit tests, do you force pump relay and then open bleed screw? or you click on outlet valve? - Hawkeye does not provide any tech support or manual whatsoever. It is a neat tool, but you are pretty much on your own using it.
I was thinking about flushing system using Hawkeye.
Thank you kindly for your input.
Joe
#47
06-27-2011, 09:53 AM
3rd Gear
Join Date: Dec 2010
Location: Coogee NSW Australia
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
modulator power bleed
Having just done the option b to remove the 3 amigo's i too was perplexed as to the exact proper way to bleed the system via nanocom.
searched high and low and found nothing and then one of the guru's here in Oz came up with the explanation of how a power bleed of the modulator works.
Check out this thread from Auslro, it has schematics and a great explain.
D2 ABS Modulator power bleed - Australian Land Rover Owners
Al Pickering
Sydney Australia
2000 D2 Td5
searched high and low and found nothing and then one of the guru's here in Oz came up with the explanation of how a power bleed of the modulator works.
Check out this thread from Auslro, it has schematics and a great explain.
D2 ABS Modulator power bleed - Australian Land Rover Owners
Al Pickering
Sydney Australia
2000 D2 Td5
Thread
Thread Starter
Forum
Replies
Last Post
BIGTSV
Discovery II
11
07-31-2013 05:36 PM
