Losing rear brake after a good bleed.

patrickg450

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Just found this thread, same here on my s10 2011. Looks like it's spiralling up. I'll tell you more guys - half a year ago I was looking for part on the fog lights kit, and found a disassembled s10 owner that had spare ABS unit that time. I've just contected him and he said "yeah, I'm still willing to sell it, but only after the season will be over" - 'cause at the time this unit is installed on his own bike. I've asked him if he lost the rear brake too - and bingo - he did.

P.S. My unit had like ten times more dirt inside. Literally loads.

did you report it to NTSB?
 

scorch

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Just update of my situation. I thought it was the abs. But i bought a master cyinder on ebay for 30$ installed it hoping it was just the master cylinder and it was. I think the rebuild kids are more expensive than buying another unit. If you bleed the brakes and it loses the rear after a while it might be time to rebuild your master cylinder.
 

patrickg450

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My country is out of its jurisdiction, as the country of origin is - my bike is imported from Japan, I'm the third owner.
where are you from? I assumed the states.

Just update of my situation. I thought it was the abs. But i bought a master cyinder on ebay for 30$ installed it hoping it was just the master cylinder and it was. I think the rebuild kids are more expensive than buying another unit. If you bleed the brakes and it loses the rear after a while it might be time to rebuild your master cylinder.
When I was fighting mine, I pretty much replaced/rebuilt everything in the brakes. The District Rep happened to stop by the shop when my bike was there, and he told us before looking a the bike it was not the ABS pump. Must have been a script from Japan (IMO), he was wrong it was the pump. But I replaced EVERYTHING before that and the brakes would come back then fade........
 

Thetractorman

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Just update of my situation. I thought it was the abs. But i bought a master cyinder on ebay for 30$ installed it hoping it was just the master cylinder and it was. I think the rebuild kids are more expensive than buying another unit. If you bleed the brakes and it loses the rear after a while it might be time to rebuild your master cylinder.
Did exactly the same. Problem came back after a couple of weeks. Tried an oe repair kit and again lasted a couple of weeks. Turned out, it was the pump after all. Couldn't justify a new or reconditioned unit on a 7 year old bike and went for straight set up bypsss with no abs. Would have have preferred to have kept the abs, but now I have really sharp 'ordinary' brakes with excellent feed back.

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Sierra1

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So, what is causing the pump failure? Is the bleed causing it? Or, is it just a coincidence? Seems too frequent to be coincidence though.
 

scorch

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Did exactly the same. Problem came back after a couple of weeks. Tried an oe repair kit and again lasted a couple of weeks. Turned out, it was the pump after all. Couldn't justify a new or reconditioned unit on a 7 year old bike and went for straight set up bypsss with no abs. Would have have preferred to have kept the abs, but now I have really sharp 'ordinary' brakes with excellent feed back.

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How did you bypass it? Im not familiar with it. Did you remove the abs unit completely and got different lines?
 

Thetractorman

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How did you bypass it? Im not familiar with it. Did you remove the abs unit completely and got different lines?
New kevlar lines on a straight 'race' set up. As said great feel and bite, but no abs.
I removed the old lines (there's alot) but left the pump and wiring alone, so there's no fault lights.
I liked the Yamaha semi linked system but reconditioning was approx £600. I spent the first 30 35 years of riding without any abs, and I don't care about resale value. I've a 2013 with 65000 miles and counting.
Apparently, a combo not 'cycling' the pump regularly means it rusts from the inside out. Plus, look we're it's situated!
There was alot of very informed discussion on the forum back about Oct 19. A guy in New Zealand knew a great deal about abs units. You can seal off the rear alone, so you still have abs on the front and no fault lights. Make a U shaped brake line across the rear 2 lines at back of the pump. There's a really good and informative thread in the forum around Oct 19 inc photos and how to recycle. Made me feel stupid for not having recycled it earlier.
I didn't do the rear isolation, based on the worry that if the back has gone, when will the front go? So redid them both.

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patrickg450

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So, what is causing the pump failure? Is the bleed causing it? Or, is it just a coincidence? Seems too frequent to be coincidence though.

near as I can tell, the seal is bad and allows air it get it @ the ABS unit. There was an Aussie or NZ that had done a good write up on making a new one. I think it worked. Mine and a few guys I know, had their drain hole that houses the unit clogged up and it held water/dirt crap. When the ABS was exposed to this it ingested the crap and ruined the seal thus allowing air to get by and into the brake system. I have only seen it effect the rear brake, not the front. People think they just need a bleed but it comes back.
 

Doug C

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So, what is causing the pump failure? Is the bleed causing it? Or, is it just a coincidence? Seems too frequent to be coincidence though.
The member from South America (Jlq1969 I think) suggested it was possibly from pushing the rear caliper piston back in when replacing the rear pads, introducing air into the abs pump.
I did go through the gradual loss of rear brakes and was prepared to replace the pump unit. I tried replacing the rear master cylinder first as it was cheaper. Two years of good brakes since then. Lucky maybe.
 

Tupai

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My vacuum bleeder turned up today so I had another play.
I made up a pipe to bypass the rear side of the ABS unit. Sealed up the bleed nipple with some thread tape and sealed the rear reservoir cap and sucked the system down to 20 inHg. It held at 20 for a good 1/2 hr.
I then made up a blanking pipe and tried to suck the rear side of the ABS unit but it wouldn’t hold and settled at 2inHg. View attachment 50418
Something inside the ABS unit is leaking air, my guess would be the seal on the shaft of the motor as everything else is sealed.
I made up another pipe to complete the rear side of the ABS,filled it with fluid and installed the pipe, bled the rear and went for a ride.
The rear brake feels fantastic, obviously no ABS but it’s so powerful it made me smile. Went down a gravel road and fired the front ABS several times and came home with no ABS faults.
I have had air introduced to the front brake twice now when using unified braking so I’ll either have to bypass it, fix it or replace it.
I’ll have a go at fixing it next time I’m feeling brave.
Hi just wanted to ask the fittings pipe size and the nut size
 

Steve in ATL

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Please file with NTSB, according to the FACTORY MANUAL. A ABS failure will not cause a brake failure, so going by their own document this is NOT suppose to happen.
Holy Thread Resurrection!

For clarification: Vehicle Safety Defects are, in the United States, reported to NHTSA, not the NTSB. Here's the link.

This certainly is a safety issue / defect and if you have had it you should report it. This is how recalls are born, folks.

Don't just whine about it on a forum - report it!
 

Jlq1969

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Not for long! I have a friend, who’s a vehicle, recall, attorney, and I’m having him help me write my complaint, so that it is the most effective that it can be.
That letter of complaint, you must accompany it with the receipts of "all" the services carried out in an authorized Yamaha workshop, and that the work carried out on the motorcycle coincides with the maintenance manual and their respective intervals... to rule out the intervention from someone “unauthorized”……that way, the investigative agency can pay attention to a claim (because they can have the correlation of all the activities carried out on the motorcycle)….
 

MattR

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That letter of complaint, you must accompany it with the receipts of "all" the services carried out in an authorized Yamaha workshop, and that the work carried out on the motorcycle coincides with the maintenance manual and their respective intervals... to rule out the intervention from someone “unauthorized”……that way, the investigative agency can pay attention to a claim (because they can have the correlation of all the activities carried out on the motorcycle)….
I’m guessing that if you haven’t followed servicing schedules perfectly including such things as changing brake hoses, calipers seals and master cylinder pistons and seals as required in the workshop manual, they will have an out


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Jlq1969

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they will simply file the complaint….but “we” know that there are user reports of rear brake loss…..we also know that under no circumstances should the abs module cause that brake loss, not even decrease the capacity of braking.....but reality tells us that it "occurs"......now, it occurs due to an internal failure of the module....or the internal failure is caused by a procedural error......We also know that the failure is not "endemic ”…..some fail, and many don't. Maybe when changing pads (without loosening the bleeders), some push the caliper pistons “vigorously”…..and others do it “slowly”…….and that makes the difference…..it's all assumptions….. Sometimes when the rear brake has been lost...riders have bleed the brake and found air, got the brake back and on. to lose it again, they purged again, and they found air again… that air does not necessarily enter from the outside. In fluid dynamics, if a fluid under pressure escapes through a small hole (and passes at high speed to another area of low pressure), that fluid gasifies (forms bubbles)…..that small hole could be a valve internal module, poorly closed, due to some dirt
 

RCinNC

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There's a difference between a warranty claim/defective product claim and a product safety issue.

Trying to prove a product is defective does open up all those counterclaims from a manufacturer that you neglected maintenance, or the product was used improperly outside its original intent.

If someone actually loses their brakes because an ABS module fails, then that's a whole different issue. A braking system still has to be able to function even if the ABS module fails. Under 49 CFR Section 571.135- Standard No 135; Light Vehicle Brake Systems, under S7.8.3, it says that for service brakes on a vehicle equipped with one or more antilock systems, in the event of any single functional failure in any such system, the service brake system shall continue to operate and shall stop the vehicle as specified in S7.8.3(a) or S7.8.3(b).

So if your actual braking system has failed because an ABS module failed, that's a violation of the consolidated federal standards for ABS, and is most definitely an issue that should be reported to the NHTSA. Under that CFR statute, it doesn't matter if you never changed your brake fluid, brake hoses, of let the module sit in swamp water for a year; the brake system has to remain functional in the event of an ABS module failure. It's a product safety issue. A complaint to the NHTSA isn't about "Yamaha/Bosch makes a crappy ABS unit and I want a refund" , it's about "Yamaha's braking system as designed doesn't comply with the federal regulations regarding antilock equipped braking systems".

If you can't get a functional brake in the rear after it's been properly bled, and the only way you can achieve a functional rear brake is to replace the ABS module, then this point needs to be driven home with the NHTSA. If you're being told by a Yamaha dealer or an independent mechanic that the only way to rectify the problem is to replace the ABS module, then that should be thoroughly documented in your complaint, with names, dates, times, written estimates, etc.

I don't really know how widespread this issue is, as far as defective modules go; forums are great for a lot of good things, but they're also great at confirmation bias. But even one failure of what is supposed to be a fail-safe system is too many.
 

cyclemike4

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ky
I don't know why I never thought of filing a brake issue on my dodge truck. Something on that truck was broke at the very least every 6000 miles from new. I took that truck back and took it back and took it back till the warranty ran out. Actually I got tired of taking it back for multiple issues so I just started fixing things myself. The brakes on it would fail and the pedal would go to the floor! nothing at all. you could not pump them nothing. Of course they could not see a thing with a scan it would be working when the service people checked it. I went through red lights and across traffic at times. I just stopped driving it unless I absolutely had to have it. I pulled the fuse to the abs and the brakes worked but the speedo would not work and the truck would not idle. So I pulled the plug to one of the wheel sensors and I have never lost brakes like that again. It doesn't have abs now but it much easier to stop on ice and slick roads than it was with it working. If all four wheels were on ice the pedal would go to the floor with it working. Well that whole truck Dodge should have bought back. Junk from day one. It is 21 years old now and will never see 100,000 miles.
 
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