Nissan 19mm radial master cylinder seal kit

[ssray]

My nissan radial master cylinder has decided to go technical 

It's pressuring the system but the lever is going hard and not returning to it's resting place, it's as far from the bars as possible and keeping the brakes on 

It's a gsxr 19mm radial master cylinder 

I've looked at a few rebuild kits but am not sure which one 

It's only marked with 3/4 underneath 

[TLRS]

Before ordering anything maybe take it apart? Maybe it’s a plugged hole.

[ssray]

2 hours ago, TLRS said:

Before ordering anything maybe take it apart? Maybe it’s a plugged hole.

I'm going to do that and stick it in the ultrasound cleaner as well 

[TLRS]

3 hours ago, ssray said:

I'm going to do that and stick it in the ultrasound cleaner as well 

Does it have an aftermarket lever?

[ssray]

1 hour ago, TLRS said:

Does it have an aftermarket lever?

No, std one 

[ssray]

Aaaaaaaaaa

This morning I stripped the master cylinder Down and cleaned it, nothing blocking any holes or passageways.

So I refitted it and bled the system, got full pressure fairy quickly.

Went for a ride, stopped after about half a mile and all was ok, got a bit further and the R/h disc was quite warm, the lever was very firm with hardly any freeplay 

The disc was pretty hot then, I ended up stopping,not of my own free Will 

The R/h disc was very hot,the lever was solid,I took a 8 mm spanner with me so let some pressure out, quite a squirt.....

Aimed for home and had to stop again and release more pressure 

When I got home I took the pads out , the caliper pistons I can push back with my thumbs.

I'm thinking of taking the pistons out and cleaning etc

The brembos radial calipers I have are supposed to be a bugger to get right if you fully split them 

I'm going to fish the old pads out of the bin and try them, as I have just put a new set of ebc's in

 

[ssray]

When the system was first bled there was really good release from the calipers, I'd put the brakes on hard at a standstill and when released there was no friction that you would associate with drag/stiction

[TLRS]

When the calipers are bolted up and you squeeze the lever, can you see the discs move or flex in any way?

Does sound like the pressure has nowhere to go. If the hole is clean.. maybe the piston blocks it in some way.. only when riding? Very peculiar. Is everything well with the reservoir? Cap, rubber thingymabob.. fluid level?

[ssray]

6 hours ago, TLRS said:

When the calipers are bolted up and you squeeze the lever, can you see the discs move or flex in any way?

Does sound like the pressure has nowhere to go. If the hole is clean.. maybe the piston blocks it in some way.. only when riding? Very peculiar. Is everything well with the reservoir? Cap, rubber thingymabob.. fluid level?

Level fine and didn't appear to rise.

I'm fitting the old pads today, just been through the bin to get them(bin day)

If not it's pistons out without splitting the calipers (BMW r1200rt 2018)

[TLRS]

1 hour ago, ssray said:

Level fine and didn't appear to rise.

I'm fitting the old pads today, just been through the bin to get them(bin day)

If not it's pistons out without splitting the calipers (BMW r1200rt 2018)

That bike got abs right?

[ssray]

6 minutes ago, TLRS said:

That bike got abs right?

Not as far as I'm aware, shouldn't make a difference with the calipers, was ok till new pads....

[ssray]

I've just swapped one side, the side that gets hottest to the old pads 

I've used a electronic micrometer to measure the new and old pads and apart from the obviously (new pad material) they are within 0.01 of each other 

Off for a ride round the block for 

[ssray]

The discs still got warm , not hot but I didn't want to risk the dust carragway.

Thinking of taking the pistons and seals out and gIvinghoe it a good clean 

[ssray]

Not had any time to do much, I've given the disc bobbins a clean and spun them round with a drill to clear any crap out.

Hoping tomorrow I can get the pistons and seals out for a clean 

[ssray]

I've had time today to strip the calipers, they are only sodding monoblock.....

So far I've had two pistons out,cleaned , new seals and easily pushed back with thumb pressure, then bled the system so I could do the other two pistons 

So far I've done 7 out of the 8.

Currently at my daughter's keyboard lesson 

To get the last one out I'm going to have to bleed the system again so I can pop it out

The new pads have some odd wear marks, they have not anywhere near been bedded in yet, it's almost as if the surface isn't completely flat, so wear at the front and back of each pad but it looks untouched in the middle.

I've measured the old and new with a micrometer and they are more or less exactly the same, the new ones are ebc and I'm assuming the old are oe BMW.

I'll take a picture and post it, everything else looks as it should, 

[ssray]

The Matt bit in the middle appears to currently be unused.

 

I've managed to get the last piston out, cleaned and back in.

Bleeding took ages, usually it's tap the lever and a few tiny bubbles appear, vacuum bleeder on one caliper the the other then bled normally.

I couldn't even get fluid from the top master cylinder bleed nipple.

So I put some hose on it, filled with fluid, I'd pump the lever a few times and then open the nipple and get a bit of air out, then I'd have the bleed nipple open and allow it to suck fluid in, it looks like I had a air lock.

Took ages to bleed and I've still got a squash lever, I've tied it back overnight and we will see in the morning 

 

 

[426hemi]

13 hours ago, ssray said:

I've had time today to strip the calipers, they are only sodding monoblock.....

So far I've had two pistons out,cleaned , new seals and easily pushed back with thumb pressure, then bled the system so I could do the other two pistons 

So far I've done 7 out of the 8.

Currently at my daughter's keyboard lesson 

To get the last one out I'm going to have to bleed the system again so I can pop it out

The new pads have some odd wear marks, they have not anywhere near been bedded in yet, it's almost as if the surface isn't completely flat, so wear at the front and back of each pad but it looks untouched in the middle.

I've measured the old and new with a micrometer and they are more or less exactly the same, the new ones are ebc and I'm assuming the old are oe BMW.

I'll take a picture and post it, everything else looks as it should, 

Check that the pads are flat, I’ve seen warped pads before, I had a nissin caliper that wouldn’t bleed and tried everything and nearly threw my tools over the workshop and it was the pads warped, it was acting like a spring in the caliper, looking at them you couldn’t tell they were warped until you put them on a flat plate, put some metal blocks in the caliper and it bled straight up.

Edited September 25 by 426hemi
Add extra

[David W]

I got into the habit of bleeding brakes with the pads out and the pistons pushed all the way in. Less places for bubbles to hide.

Another trick is to bleed the system, run the reservoir as low as you can then push all the pistons back into the calipers so it pushes the fluid back up into the master cylinder. This last thing might help you understand what is causing the blockage?

[ssray]

2 hours ago, 426hemi said:

Check that the pads are flat, I’ve seen warped pads before, I had a nissin caliper that wouldn’t bleed and tried everything and nearly threw my tools over the workshop and it was the pads warped, it was acting like a spring in the caliper, looking at them you couldn’t tell they were warped until you put them on a flat plate, put some metal blocks in the caliper and it bled straight up.

I've fitted the old pads for bleeding, this morning I took the strap off of the brake lever but it's still spongy, have replaced it with the lever against the bar.

 

[David W]

@ssray just to add to above, be very careful when pushing the pistons back in. You’d be surprised how much a jet of brake fluid can cover when it comes out the reservoir at escape velocity.

Ask me how I know this 😂

[426hemi]

1 hour ago, ssray said:

I've fitted the old pads for bleeding, this morning I took the strap off of the brake lever but it's still spongy, have replaced it with the lever against the bar.

 

I tried everything with mine, normal bleeding, reverse bleeding, vacuum bleeding, pushing pistons back, tie the lever back and none worked, solid blocks between the pistons and it bled straight up, bottle of brake fluid and two days lost swearing.

[ssray]

I have a firmer lever, I've had the lever tied back for two days, when I pass the bike I undo the strap and then tie it back again, getting firmer, maybe a test ride tomorrow 

[ssray]

I've just refitted it and bled the system.

It's been in the ultrasound cleaner for about an hour, I've shone a bright torch through the tiny holes in it and got light the other side, not sure if it allowed light before though as I don't check.

Raining and up at 0220 tomorrow, test ride will have to wait 

[EvilSpike]

I had this problem with the 19mm radial Nissin master cylinder on the Honda a while back. I'd split the callipers to service them and could not for the life of me get a firm lever when everything was back together. I tried the usual squeeze/open/close/release way, tried using my manual vacuum bleeder. I tapped all the lines with a rubber mallet, rotated the master cylinder on the bars so the bleed was as high as possible, pushed fluid from the callipers to the master.  Took it in the van to the LBS for Brett to use his compressor driven vacuum bleeder. Squeezed the lever and opened the banjos a tiny fraction of a turn and let fluid out.

Nothing worked. Absolutely threaders.

Bought a Brembo RCS19 off Mark, replaced the radial Nissin did the above again, except this time I was in the garages at Portimao. Still couldn't get a decent lever feel. Went to see the tyre guy to see if he had any ideas or a vacuum bleeder. A Dutch chap with a roller cab full of tools asked why I was looking so pissed off? Told him my travails, he came over, cracked the master cylinder dual banjo bolt (the same as I'd done) and a big glob of air burped out.

I hugged the somewhat mystified Dutch chap, topped the system up, threw the bodywork on then went out an lapped Portimao with gay abandon.

I lost hours to that cunting thing. So if I were you, I'd do all of the things I did above, especially gently tapping the lines to try and encourage any bubbles to migrate to the top of the system, then after five minutes of agitation bleed from the higher most nipple. After covering everything with rags, try cracking the banjos open a fraction allowing fluid and hopefully an air bubble to bleed from there too.

Then go and find yourself a large chap from the Netherlands. Good luck.

Edited October 9 by EvilSpike

[ssray]

15 minutes ago, EvilSpike said:

I had this problem with the Honda a while back. I'd split the callipers to service them and could not for the life of me get a firm lever. I tried the usual squeeze/open/close/release way, tried using my manual vacuum bleeder. I tapped all the lines with a rubber mallet, rotated the master cylinder on the bars so the bleed was as high as possible, pushed fluid from the callipers to the master.  Took it in the van to the LBS for Brett to use his compressor driven vacuum bleeder. Squeezed the lever and opened the banjos a tiny fraction of a turn and let fluid out.

Nothing worked. Absolutely threaders.

Bought a Brembo RCS19 off Mark, replaced the radial Nissin did the above again, except this time I was in the garages at Portimao. Still couldn't get a decent lever feel. Went to see the tyre guy to see if he had any ideas or a vacuum bleeder. A Dutch chap with a roller cab full of tools asked why I was looking so pissed off. Told him my travails, he came over, cracked the master cylinder dual banjo bolt (the same as I'd done) and a big glob of air burped out.

Hugged the somewhat mystified Dutch chap, topped the system up, threw the bodywork on then went out an lapped Portimao with gay abandon.

I lost hours to that cunting thing. So if I were you, I'd do all of the things I did above, especially gently tapping the lines to try and encourage any bubbles to migrate to the top of the system then after five minutes of agitation bleed from there. And also after covering everything with rags try cracking the banjos a fraction too and allowing fluid to bleed from there.

Than go and find yourself a large chap from the Netherlands. Good luck.

Danka val

[ssray]

Managed to Go for a ride and......no difference 

So start off good lever feel, not much movement before the brakes bite, at a standstill brakes on hard push forewood and release them they release really well, no sound or scraping.

Did about a mile the discs were slightly warmer but not hot.

Went a bit further and stopped again,the discs were warmer on the R/h side

Up the dual carriageway and parked up deffo quite warm now, not too hot to touch so I head home, lost the movement in the lever fairly near home, at home the R/h disc was pretty warm not too hot to touch, the lever had no movement before the brakes bit and pushing it down the drive there is noise of the brakes rubbing 

The pads were pretty warm too .

I'm guessing the pads are dragging (just rebuilt and lubed) the master cylinder appears as clean as possible as it's been ultrasound cleaned for an hour, used a torch to check all holes were clear.

I'm sure the pads are sticking, heating up and warming the fluid enough to increase the pressure, not sure why.

I've got a brembo master cylinder arriving soon ..........

[EvilSpike]

I'm sure you don't want to be doing this but:

If you can pop the pistons out of the callipers then fish the seals out, are the seals swollen? If not are the seal grooves in the callipers filled with road crud and corrosion?

I've had fluid seals that have expanded in the past. they caused my pads to drag continually and put heat into the system.

You can either leave the seals in a bath of brake cleaner for a while to strip the moisture out of them, or buy new seals. The seals I bought from Powerhouse swelled up like this, but so did the first set of OEM ones. Changing brake fluid helped, although I have absolutely no idea why, and so far the second set in my Nissin callipers on the RC45 are working perfectly with no drag whatsoever.

[ssray]

10 hours ago, EvilSpike said:

I'm sure you don't want to be doing this but:

If you can pop the pistons out of the callipers then fish the seals out, are the seals swollen? If not are the seal grooves in the callipers filled with road crud and corrosion?

I've had fluid seals that have expanded in the past. they caused my pads to drag continually and put heat into the system.

You can either leave the seals in a bath of brake cleaner for a while to strip the moisture out of them, or buy new seals. The seals I bought from Powerhouse swelled up like this, but so did the first set of OEM ones. Changing brake fluid helped, although I have absolutely no idea why, and so far the second set in my Nissin callipers on the RC45 are working perfectly with no drag whatsoever.

I did have them fully apart, turns out they are monoblocks , so it was two pistons out clean the grooves etc, didn't know about the seals expanding, I just cleaned them and red rubber grease everywhere, including the grooves as I feel it gives a bit better protection.

I'll try soaking in brake cleaner thanks 

[dansp1]

Is it a standard brake lever?

[ssray]

4 hours ago, dansp1 said:

Is it a standard brake lever?

Yes,