ABS unit blocked on front brake circuit.............

[Mihalis fjr]

So,we waiting...

I am very curious as many others here i believe,what the @#$&%*@ caused this problem..

I think that something,i don't know what,blocked the passage there..

Absolutely agree with that . But I am not going to waste any more time or effort to try and find out what it was. We are talking about a very tiny piece of something which is very likely to get lost in all the 'filings' if I try to hacksaw into the valve that was blocked....................

Also agree,if you try to cut it,a lot of filings will go in the passages and you will never find what really caused the blockage..The most important is that now your bike works fine with a low cost repair!

Anyway,thanks for the pictures and details

 

[Donal]

An update on screening debris from the valve seat. While clearing the bench I found the remains of a plastic screen. It looks like it would have protected the valve from anything coming back from the brake caliper.

Screen

In position (can't see where else it would fit).

Got a sheet of 90 micron filter media (stainless steel) this morning.

The material is 0.095mm (0.0037") thick so no need to modify the banjo union. The union is 8.2mm wide, so just need a strip ~8mm wide and long enough to overlap around the banjo bolt.

PS Anyone reading this is automatically sworn to secrecy. The scissors on the right are my Wife's best (Sabatier Professional).....

Having 'discovered that the 'return' lines are already protected (internally), I just need to carry this out on the front & rear lines from the master cylinders. The ideal spot is where the lines terminate at the ABS block.

My only slight concern is that several people have recorded failures of their rear brake ABS circuit. Still mulling over that one...............

 

[mcatrophy]

<snip>

PS Anyone reading this is automatically sworn to secrecy. The scissors on the right are my Wife's best (Sabatier Professional).....

<snip (haha)>

You'd better get your bike going soon so you can RUN when she finds out. And she will. They know without being told.

I'd never ever, ever dare to use my wife's scissors for anything.

And thanks for showing us your dissection. As far as I can remember, you are the first to post up such pictures.

 

[Donal]

<snip>

PS Anyone reading this is automatically sworn to secrecy. The scissors on the right are my Wife's best (Sabatier Professional).....

<snip (haha)>

You'd better get your bike going soon so you can RUN when she finds out. And she will. They know without being told.

I'd never ever, ever dare to use my wife's scissors for anything.

And thanks for showing us your dissection. As far as I can remember, you are the first to post up such pictures.

Things could be about to get worse. Just got off the phone with the shop who are doing my forks. Part of the deal was to get the lower fork tubes powder coated while they were stripped down. The call was to tell me there were two minor scratches and wanted to know if they should return them to the powder coaters. I wasn't prepared to wait another 2-3 weeks so agreed to accept them as is.

Larry (shop owner) told me the best thing to use was nail varnish. I don't (normally) use the stuff, I wonder where I might find some?...................

Appreciate the comment, but no thanks necessary - I get far more from this Forum than I could ever contribute, it's just nice to get a chance to add to the growing body of knowledge...........

 

[Mihalis fjr]

Good work Don!In your first photo this thing looks like a filter,i am very curious how something could pass through this filter and caused the blockage?!Very strange..Perhaps something came from the other way and not from the callipers,a thought..Αs for the nail varnish,i have used it in the past,to repair some deep scratches on my rear wheel after a tire changing.Yes,the nail varnish works great for about one year.After that,i noticed that the color became a little yellowish.Perhaps from the sun,i don't know,but you can repaint it and that's it.Also you can use a touch up pen in the same color with your forks.

 

[Donal]

Good work Don!In your first photo this thing looks like a filter,i am very curious how something could pass through this filter and caused the blockage?!Very strange..Perhaps something came from the other way and not from the callipers,a thought..Αs for the nail varnish,i have used it in the past,to repair some deep scratches on my rear wheel after a tire changing.Yes,the nail varnish works great for about one year.After that,i noticed that the color became a little yellowish.Perhaps from the sun,i don't know,but you can repaint it and that's it.Also you can use a touch up pen in the same color with your forks.

I guess I didn't explain it very well, so here goes again........

During 'normal' operation the solenoids are de-energised, which means the Inlet valves are held open by the spring pressure acting from below.

In this picture you can see where the spring is in relation to the poppet.

In this position, when you operate the brake lever fluid flows from the master cylinder to the caliper through the bottom of the valve seat

and out though the port in the side of the valve retainer

this port is where the 'filter' fits IMO

When fluid 'returns' from the caliper, it passes through the filter before entering the valve seat, so the system is protected from that direction.

That is why I think a filter in the line before the Inlet valve is a good idea.

 

[Blind Squirrel]

I have changed the fluid annually just to be on the safe side but................

Do you also cycle the ABS on a frequent (4-6 week) basis to keep "fresh" fluid flowing through it?

 

[Donal]

I have changed the fluid annually just to be on the safe side but................

Do you also cycle the ABS on a frequent (4-6 week) basis to keep "fresh" fluid flowing through it?

Not a 4-6 week basis, but yes every time I service the bike - about every 3000 miles (I do ~10,000 miles per year).

 

[Donal]

Thought the ABS block diagram may help....

 

[Mihalis fjr]

Don,thanks again for the details!The mama Yamaha should have done something to prevent this thing to happens,but of course she wants to sells spare parts.The revenue of the companies comes from the spare parts,and not from the sells of their bikes from what i know.You must be sure,especially the japanese they are very smart people and a little sly,they know very well what they do..I hope that you understand me what i mean....

 

[RaYzerman19]

Thanks, Donal for the diagnostics and contributing to the knowledge base. It should be noted that this ABS block diagram is specific to '08-'12 (not sure about Gen III). The '06-'07 hydraulic units are different having external solenoids. Gen 1 is different again.

I believe we have indeed heard about GenII ABS issues, a handful of cases where the rear ABS doesn't work (mine included), and a couple where it was difficult to bleed.

 

[Donal]

Thanks, Donal for the diagnostics and contributing to the knowledge base. It should be noted that this ABS block diagram is specific to '08-'12 (not sure about Gen III). The '06-'07 hydraulic units are different having external solenoids. Gen 1 is different again.
I believe we have indeed heard about GenII ABS issues, a handful of cases where the rear ABS doesn't work (mine included), and a couple where it was difficult to bleed.

Thanks for clarifying that. One thing I forgot to mention. I could not see any sign of elastomer seals anywhere in the system. Everything (apart from the filter) is metal to metal sealing. So, if you have a blockage and are at the point of replacing your ABS there wouldn't be any harm trying some more aggressive chemicals to try and remove whatever is causing the problem. I couldn't see any signs of corrosion.

 

[Mihalis fjr]

Again,i am very curious what caused the blockage,from the way to and from the callipers the system has a filter,from the other way it is very difficult something have passed through the very small hole in the master cylinder...If something passed through this small hole in the master cylinder,surely this very small thing could passed and from the holes in the valves i believe...A very strange story.......

The mystery continues...

 

[Donal]

Again,i am very curious what caused the blockage,from the way to and from the callipers the system has a filter,from the other way it is very difficult something have passed through the very small hole in the master cylinder...If something passed through this small hole in the master cylinder,surely this very small thing could passed and from the holes in the valves i believe...A very strange story.......The mystery continues...

If you have a look at the block diagram above, there is a check (non-return) valve across the inlet valve. Fluid from the the master cylinder can only go through the inlet valve but fluid returning from the calipers can go back through the inlet valve or through the check valve, bypassing the filter..............

 

[Mihalis fjr]

Again,i am very curious what caused the blockage,from the way to and from the callipers the system has a filter,from the other way it is very difficult something have passed through the very small hole in the master cylinder...If something passed through this small hole in the master cylinder,surely this very small thing could passed and from the holes in the valves i believe...A very strange story.......The mystery continues...

If you have a look at the block diagram above, there is a check (non-return) valve across the inlet valve. Fluid from the the master cylinder can only go through the inlet valve but fluid returning from the calipers can go back through the inlet valve or through the check valve, bypassing the filter..............

I just saw it,anyway your system works fine now and with the filter where you have make there i believe that you will not have any problem again!