Gen 1 ABS not working after storage

[leedavis]

I'd take the bike out in your driveway or wherever close, lock up the rear then immediately do diagnostics and see if you can't get a code. There should be one but in my experience sometimes the system needed convincing to give it up. It's inconclusive but the weak pulse response you got from the rear test doesn't sound good to me. When you hold your foot on the brake pedal you should really feel it kick..

 

[Donal]

Sounds like a good time to get some clean fresh brake fluid in there! I know you have done it once before but now you have probably moved the 'old' fluid that was trapped in the ABS block.

Which begs the question, "If I want to REALLY clean out my brake system, is there some liquid concoction I can run through my system to REALLY clean, not just flush, but the clean the system?"

Something along the lines of having new caliper piston O-rings (to replace old ones that might get damaged by a clean, not just a flush) and run a couple of quarts of brake cleaner through the system to loosen up and remove any built-up or deposited crud, followed by a thorough flush and refill with DOT-4.

Perhaps a fill with brake cleaner, let the cleaner sit in the ABS block a couple of days, which might free up stuck spool valves, then flush and fill with the real stuff..

Anyone want to WAG for me??

FredW...Ionbeam...Odot???

I think it was you Howie who suggested on a previous post that it might be possible to activate the ABS with the bleed nipple open. Sounds good to me (in theory) but I've never been brave enough to try it

I have always gone the conservative route and flushed the system every year. The actual cost is minimal and it only takes ~15 minutes. I also 'activate' the ABS system at each maintenance, again no actual cost and it only takes ~5 minutes.

Preventative maintenance beats corrective maintenance every time IMHO.

 

[Fred W]

The test worked as it should. There was a noticible difference in pulsing between the front and rear. The front was a hard pulse and the rear was a slight pulse and vibration. Is that normal?

No, not normal for the back to just slightly pulse. It should be felt quite sharply in the brake pedal.

I think the results are encouraging that you managed to get the pump to activate. In the seized blocks that doesn't happen.

There have been other cases where the pump activates but the spools do not move properly so the fluid pressure isn't properly relieved during sensed lockup. That is what this sounds like. I'll bet that when the rear wheel is locking up during riding the pump is running and the pedal is vibrating then too, but the wheel is still locking up.

I'd take the bike out in your driveway or wherever close, lock up the rear then immediately do diagnostics and see if you can't get a code. There should be one but in my experience sometimes the system needed convincing to give it up. It's inconclusive but the weak pulse response you got from the rear test doesn't sound good to me. When you hold your foot on the brake pedal you should really feel it kick..

The fact that the wheel locks up says the ABS isn't working. The ABS fault would just confirm what we already know. And I agree with the last sentence. A faint vibration in the pedal = Not Good.

Sounds like a good time to get some clean fresh brake fluid in there! I know you have done it once before but now you have probably moved the 'old' fluid that was trapped in the ABS block.

Which begs the question, "If I want to REALLY clean out my brake system, is there some liquid concoction I can run through my system to REALLY clean, not just flush, but the clean the system?"

Something along the lines of having new caliper piston O-rings (to replace old ones that might get damaged by a clean, not just a flush) and run a couple of quarts of brake cleaner through the system to loosen up and remove any built-up or deposited crud, followed by a thorough flush and refill with DOT-4.

Perhaps a fill with brake cleaner, let the cleaner sit in the ABS block a couple of days, which might free up stuck spool valves, then flush and fill with the real stuff..

Anyone want to WAG for me??

FredW...Ionbeam...Odot???

Howie, you're better than this. Brake cleaner is for external parts and has no place in the brake hydraulics. Simply flushing with fluid and activating the ABS is as good as it gets, and more than sufficient. The most likely culprit of ABS problems is old moisture contaminated fluid. Do the maintenance with fresh DOT 4, and it should never be an issue. When the fluid is flushed, it does exchange the fluid in the ABS blocks. There may be a small amount that doesn't flush through unless the block is activated, but it shouldn't be a problem.

(best WAG I got)

+1 - I agree. The inside of the hydraulic system will be spotless once you flush out the old fluid (doesn't take quarts of fluid to flush, either). That is unless you've already let it go too long, in which case it will be corroded, not just dirty. There is nothing you can run through the system to remove corrosion, so the best thing you can do is not to allow any to form. It's so quick and easy to do a fluid flush (with the right tools or speed bleeders) why not just do one annually and stop worrying?

 

[Frushlorton]

Reaccomplished test last night with wife. Confirmed the rear wheel never moved or pulsed during test. The weak pulse still present. I will be flushing the system again to be sure a clean system. I have a weekend ride coming up for the Blue Ridge Bike Fest next weekend. Then I will be looking for a used block if it is still there.

Anyone tried the hammer to the valve block like a frozen starter yet?

 

[Fred W]

Anyone tried the hammer to the valve block like a frozen starter yet?

Honestly? No. But I think if I was faced with the situation I might be pursuaded to give it a go. I mean... what the f*^& do you have to lose, right?

There is probably a right way and a wrong way to hammer on your ABS block. I'd probably want to try and devise a way to put constant, or constantly varying operating voltage on the solenoid while I was doing all the hammering. And I don't have (or haven't yet thought up) information on how the heck to do that yet.

Still, it is an idea that is not without considerable merit.