A miserable day.

[Old Grizz]

Tomorrow I was suppose to go for a nice 500km ride to another city for my grandsons grade12 graduation.
My wife, daughter and her 2 sons were going to take the car.
2 weeks ago I noticed my rear brake pedal getting really soft.
I tried all the bleeding procedures and it worked for a bit then went soft again
I also noticed my ABS light not coming on for a few seconds on start up.
I talked to the dealer and he suggested that the ABS pump needed cycling and as I was really busy I made an appointment.
Well today I got the news.
I need a new rear master cylinder.
Ok no big deal
EXCEPT.
NONE IN CANADA, ON BACK ORDER TILL END OF JULY.
One dealer found one at a dealer in Washington.... great.....
I phoned them.. yep they have it....
NO THEY DONT SHIP TO CANADA.
It seems that their credit card machines don't accept Canadian postal codes.
Darn...so I am riding in the car.
I have a 12000 km rode planned leaving the first of Aug so it had better be fixed by then.
Yes I will do local rides with no rear brake for a month.
My bike is a 2012.


Sent from my SM-G781W using Tapatalk

[1911]

https://www.allballsracing.com/18-1075.html

[Old Grizz]

I will have to try to get one of those kits.
The rebuild will be fairly easy.
It is sure worth a try
Thanks for the info.
Of course the dealer says it's not rebuildable, so I will do it.

Sent from my SM-G781W using Tapatalk

[N4HHE]

Make sure your cylinder is still in good shape. New piston will do no good if the cylinder is pitted. If pitted a good machine shop can bore. The new piston may still work, you have little to lose.

[gixxerjasen]

Sounds like you need to tell grandson you'll have to miss his graduation to drive to Washington.

[1911]

I will have to try to get one of those kits.
The rebuild will be fairly easy.
It is sure worth a try
Thanks for the info.
Of course the dealer says it's not rebuildable, so I will do it.

Sent from my SM-G781W using Tapatalk

https://www.fjrforum.com/threads/spongy-brakes.170964/

[Old Grizz]

Make sure your cylinder is still in good shape. New piston will do no good if the cylinder is pitted. If pitted a good machine shop can bore. The new piston may still work, you have little to lose.

With the cylinder being that small I can probably hone it, if it is small scratches or bore it a small amount on the milling machine.
I am first going to put a full container of fresh brake fluid through the system and see if that helps.

Sent from my SM-G781W using Tapatalk

[Old Grizz]

I ordered the rebuild kit today
Hope that and a total system bleed fixes the problem.
I saw a 2022 FJR at the dealer today....
Damn if it hadn't been sold it sure would have been tempting

Sent from my SM-G781W using Tapatalk

[Steel_Gin]

I ordered the rebuild kit today
Hope that and a total system bleed fixes the problem.
I saw a 2022 FJR at the dealer today....
Damn if it hadn't been sold it sure would have been tempting

Sent from my SM-G781W using Tapatalk

That certainly would have fixed the brake problem.

[Old Grizz]

Update on the rear brake issue.
I decided to let the dealer check out the problem.
There was several issues with the dealer but I won't get long winded with the details.
Bottom line.
They replaced the rear master cylinder, they finally figured out how to cycle the ABS pump, which they did.
They bled the system a dozen times at the front caliper.
They bled the rear caliper.
After working on it for about 5 hours the rear master cylinder still comes up hard then goes soft.
They can hear and feel the ABS pump cycle.
They put enough brake fluid through the system to completely change it.
Has anyone else come across this problem?
Tomorrow I think I will disconnect the line from the ABS system at the rear caliper, fill it with braze and isolate the rear system from the ABS system.
Been riding without ABS since 1970 so I don't think it will be a big deal
At least then I will have a working rear brake.

Sent from my SM-G781W using Tapatalk

[raYzerman]

I doubt blocking or isolating the rear line will fix it... the problem is hydraulic, upstream of that.

I want to ask, did the ABS test produce pulses at the lever and pedal?? Particularly the pedal, I just want to know if you have rear ABS working. How many times did they repeat the ABS test?

When you bleed the system, you're bleeding the complete non-ABS system, which normally is in by-pass of the ABS fluid circuits until ABS is activated. Check out this block diagram...... When you cycle the ABS pump via the diagnostic connector, it helps purge any stale fluid out of the ABS fluid circuits between points 5, 6, and 7. If stale fluid becomes 'cholesterol', then it can cause (most likely the rear) the ABS not to function. Or cholesterol can migrate downstream from the ABS pump. Very simple, nothing much to it. Other than that, you should still have regular brakes, and you should have a hard pedal if the fluid was flushed, no air, good master cylinder (which obviously wasn't your issue).

Isolating the rear is not likely to fix anything... We'll rule out your master cylinder now that it's new. I can only think you still have air in the system being held up. Is your brake pedal hard until you push it harder? One note, in normal operation, the proportioning and metering valve delay/restrict the front right lower caliper from being applied until you press hard and fast enough. I am thinking you have some partial blockage or malfunction in the proportioning or metering valve or just before it but downstream of the ABS pump.

The next attempted fix.... undo (loosen) the steel line fittings at the metering/proportioning valve at the point furthest from the ABS block and see if you get air/fluid flow at normal pedal effort. If not, one of them is potentially blocked (with cholesterol that moved downstream). However, if they got fluid out of the front caliper, then I dunno.

Other attempted fixes, undo fittings one at a time on the ABS block in case there is blockage there, bleed while loosened.... NOTE, this is going to be messy, so keep lots of isopropanol around to mop up/rinse off. Sorry, I do not know which are for the rear, but the clue will be the one going to the proportioning and metering valves.....

If they bled this with a vacuum bleeder, it needs to be re-done with the good old fashioned way.....

Your thoughts??

[Old Grizz]

I doubt blocking or isolating the rear line will fix it... the problem is hydraulic, upstream of that.

I want to ask, did the ABS test produce pulses at the lever and pedal?? Particularly the pedal, I just want to know if you have rear ABS working. How many times did they repeat the ABS test?

When you bleed the system, you're bleeding the complete non-ABS system, which normally is in by-pass of the ABS fluid circuits until ABS is activated. Check out this block diagram...... When you cycle the ABS pump via the diagnostic connector, it helps purge any stale fluid out of the ABS fluid circuits between points 5, 6, and 7. If stale fluid becomes 'cholesterol', then it can cause (most likely the rear) the ABS not to function. Or cholesterol can migrate downstream from the ABS pump. Very simple, nothing much to it. Other than that, you should still have regular brakes, and you should have a hard pedal if the fluid was flushed, no air, good master cylinder (which obviously wasn't your issue).

Isolating the rear is not likely to fix anything... We'll rule out your master cylinder now that it's new. I can only think you still have air in the system being held up. Is your brake pedal hard until you push it harder? One note, in normal operation, the proportioning and metering valve delay/restrict the front right lower caliper from being applied until you press hard and fast enough. I am thinking you have some partial blockage or malfunction in the proportioning or metering valve or just before it but downstream of the ABS pump.

The next attempted fix.... undo (loosen) the steel line fittings at the metering/proportioning valve at the point furthest from the ABS block and see if you get air/fluid flow at normal pedal effort. If not, one of them is potentially blocked (with cholesterol that moved downstream). However, if they got fluid out of the front caliper, then I dunno.

Other attempted fixes, undo fittings one at a time on the ABS block in case there is blockage there, bleed while loosened.... NOTE, this is going to be messy, so keep lots of isopropanol around to mop up/rinse off. Sorry, I do not know which are for the rear, but the clue will be the one going to the proportioning and metering valves.....

If they bled this with a vacuum bleeder, it needs to be re-done with the good old fashioned way.....

Your thoughts??

I will give it a try. They did have fluid bleed at the front caliper.
Nor sure about exactly what they felt doing the ABS test.
They said the pump cycled as it should.
I know blocking off the line at the master cylinder will not fix anything.
It will however give me an operational rear brake. I am not concerned about having the balanced front, back braking or even abs

Sent from my SM-G781W using Tapatalk

[Old Grizz]

I doubt blocking or isolating the rear line will fix it... the problem is hydraulic, upstream of that.

I want to ask, did the ABS test produce pulses at the lever and pedal?? Particularly the pedal, I just want to know if you have rear ABS working. How many times did they repeat the ABS test?

When you bleed the system, you're bleeding the complete non-ABS system, which normally is in by-pass of the ABS fluid circuits until ABS is activated. Check out this block diagram...... When you cycle the ABS pump via the diagnostic connector, it helps purge any stale fluid out of the ABS fluid circuits between points 5, 6, and 7. If stale fluid becomes 'cholesterol', then it can cause (most likely the rear) the ABS not to function. Or cholesterol can migrate downstream from the ABS pump. Very simple, nothing much to it. Other than that, you should still have regular brakes, and you should have a hard pedal if the fluid was flushed, no air, good master cylinder (which obviously wasn't your issue).

Isolating the rear is not likely to fix anything... We'll rule out your master cylinder now that it's new. I can only think you still have air in the system being held up. Is your brake pedal hard until you push it harder? One note, in normal operation, the proportioning and metering valve delay/restrict the front right lower caliper from being applied until you press hard and fast enough. I am thinking you have some partial blockage or malfunction in the proportioning or metering valve or just before it but downstream of the ABS pump.

The next attempted fix.... undo (loosen) the steel line fittings at the metering/proportioning valve at the point furthest from the ABS block and see if you get air/fluid flow at normal pedal effort. If not, one of them is potentially blocked (with cholesterol that moved downstream). However, if they got fluid out of the front caliper, then I dunno.

Other attempted fixes, undo fittings one at a time on the ABS block in case there is blockage there, bleed while loosened.... NOTE, this is going to be messy, so keep lots of isopropanol around to mop up/rinse off. Sorry, I do not know which are for the rear, but the clue will be the one going to the proportioning and metering valves.....

If they bled this with a vacuum bleeder, it needs to be re-done with the good old fashioned way.....

Your thoughts??

I will give it a try. They did have fluid bleed at the front caliper.
Nor sure about exactly what they felt doing the ABS test.
They said the pump cycled as it should.
I know blocking off the line at the master cylinder will not fix anything.
It will however give me an operational rear brake. I am not concerned about having the balanced front, back braking or even abs

Sent from my SM-G781W using Tapatalk

After checking its not going to be easy to isolate the rear brake. In checking some things I need to order the hose from the master to the abs block.
Then I can do further diag.
When bleeding the rear.
It is soft, after repeated cycles it comes up hard, then holding it down, it goes soft and no brake action.
Never seen that before on any brake system.
It's like air somehow seeps into the system.

Sent from my SM-G781W using Tapatalk

[wheatonFJR]

I'm not a mechanic, but that sounds like a bad master cylinder. Anybody else feel the same way?

[N4HHE]

I'm not a mechanic, but that sounds like a bad master cylinder. Anybody else feel the same way?

Yes. When it "goes soft" after being firm that can only be a leaking piston on the caliper, a burst hose, or leaking past the piston of the master cylinder. The first two present additional symptoms that would be hadhard to miss.

[raYzerman]

Agreed, it's bypassing somewhere, but where..... he's got a new master cylinder I believe, so........ this is a mystery, and there has to be an explanation.

Thought on the line you're talking about..... if you loosen the fitting at the ABS block, it should "leak" fluid out the fitting, i.e, that line isn't blocked if that's what you were thinking...... and if you can bleed the system, that line can't be blocked.

If using a vacuum bleeder, time to put that away. Might be sucking air through the threads of the bleeder screws, not getting the system purged.

I don't think we're sure what the dealer did, so have to start at the beginning so we know where we are......

Start by bleeding the right front lower caliper (rear linked brake line) first. Pedal will be soft while you pump fluid, use good strong strokes of the pedal and let it up quickly. Don't open the bleeder screw any much more than say 90 degrees so there is some fluid resistance. When done, close the bleeder and pump the pedal (should be harder), and while holding it, crack the bleeder a bit, pedal will go down somewhat, close the bleeder when that happens. Try the pedal again, and hold it, should now be firm.

Now do the same at the rear caliper. Try the pedal, should now be perhaps even a little firmer.

Note do not let reservoir run dry at any time. If you see air bubbles, keep bleeding until gone (let us know how this went).... however, if the OEM bleeder screws are too loose, you'll perhaps get air bubbles. IF you like, rub some grease around the threads to prevent air. IF you have some silicone surgical tubing (2.5-3mm ID), it is the best bleeder hose (the same stuff Speedbleeders gives you). Route your bleeder hose so you have a loop of hose above the bleeder screw before it goes into your collection bottle.

[raYzerman]

The idea now is to have a first hand account of how it went, and need your interpretation of "soft pedal" when you're done. IF you now press on the pedal it should be reasonably firm and while holding it, not go soft. IF you can still press harder and then feel soft, there is one more step to take.... get a bungie cord and tie the pedal down to the centerstand and leave it overnight..... should be firmer in the morning as any bits of air in the plumbing around the ABS pump or rear caliper should migrate up into the reservoir.....

[Bugnatr]

The idea now is to have a first hand account of how it went, and need your interpretation of "soft pedal" when you're done. IF you now press on the pedal it should be reasonably firm and while holding it, not go soft. IF you can still press harder and then feel soft, there is one more step to take.... get a bungie cord and tie the pedal down to the centerstand and leave it overnight..... should be firmer in the morning as any bits of air in the plumbing around the ABS pump or rear caliper should migrate up into the reservoir.....

Try this first, I have used this method more than once and it works! In fact I bled the brakes and the clutch fluid on my S10 a couple weeks back. Damn if I didn't have a soft clutch lever when finished, that clutch fluid reservoir is really small which doesn't help the bleeding process. Anyway, strapped the clutch lever fully engaged and turned the bars to put the reservoir at the high point and the next morning all was good! A nice 300 mile ride in the hills confirmed this.

[Old Grizz]

I'm not a mechanic, but that sounds like a bad master cylinder. Anybody else feel the same way?

That's what the dealership told me.
I told them to check the abs system, they didn't, they just ordered then changed the master cyl. Didn't do a damn thing to correct the problem.
Now I have a nice shiny new master cyl that I told them I would not pay for.
I don't pay for. ...let's change this and see what happens parts.
FYI..I am a red seal commercial transport mechanic and have been for a very long time.
I also ran 4 different service departments.

Sent from my SM-G781W using Tapatalk

[Old Grizz]

Agreed, it's bypassing somewhere, but where..... he's got a new master cylinder I believe, so........ this is a mystery, and there has to be an explanation.

Thought on the line you're talking about..... if you loosen the fitting at the ABS block, it should "leak" fluid out the fitting, i.e, that line isn't blocked if that's what you were thinking...... and if you can bleed the system, that line can't be blocked.

If using a vacuum bleeder, time to put that away. Might be sucking air through the threads of the bleeder screws, not getting the system purged.

I don't think we're sure what the dealer did, so have to start at the beginning so we know where we are......

Start by bleeding the right front lower caliper (rear linked brake line) first. Pedal will be soft while you pump fluid, use good strong strokes of the pedal and let it up quickly. Don't open the bleeder screw any much more than say 90 degrees so there is some fluid resistance. When done, close the bleeder and pump the pedal (should be harder), and while holding it, crack the bleeder a bit, pedal will go down somewhat, close the bleeder when that happens. Try the pedal again, and hold it, should now be firm.

Now do the same at the rear caliper. Try the pedal, should now be perhaps even a little firmer.

Note do not let reservoir run dry at any time. If you see air bubbles, keep bleeding until gone (let us know how this went).... however, if the OEM bleeder screws are too loose, you'll perhaps get air bubbles. IF you like, rub some grease around the threads to prevent air. IF you have some silicone surgical tubing (2.5-3mm ID), it is the best bleeder hose (the same stuff Speedbleeders gives you). Route your bleeder hose so you have a loop of hose above the bleeder screw before it goes into your collection bottle.

I have done all of the above and so has the dealer.
They even tried back bleeding it with a big syringe.
They did get the abs pump to cycle using the jumper but I don't know what they felt when they did it, or if they tried bleeding the abs block while doing it.
In my 40 plus years of pulling wrenches I have bled a lot of brake and had systems over the years so I know how to do it and a few tricks.
I think I am going to pull the rear caliper and have a look at the seals

Sent from my SM-G781W using Tapatalk