Rear brake bleed order. Just confirming...

[Banks412]

Just want to Make sure I have the process right for bleeding my linked left front and rear brakes.

 

1. Bleed rear brake

2. Bleed front left brake.

 

Do do I need to bleed the spot up by the battery as well? If so, where in the steps listed do I do that? I also posted a pic of what I believe to be the bleeder valve up by the battery/ignition. Thanks in advance guys!

 

 

Also, just a side note, but does anyone know why when I post a pic it almost always seems to get turned sideways?

[cowpuc]

Just want to Make sure I have the process right for bleeding my linked left front and rear brakes.

 

1. Bleed rear brake

2. Bleed front left brake.

 

Do do I need to bleed the spot up by the battery as well? If so, where in the steps listed do I do that? I also posted a pic of what I believe to be the bleeder valve up by the battery/ignition. Thanks in advance guys!

 

 

 

Also, just a side note, but does anyone know why when I post a pic it almost always seems to get turned sideways?

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GOOD EYE and yes, that bleeder up on the neck is a vital part of getting good brakes!! I would do rear caliper, then front caliper and then the high spot bleeder up on the neck. I have been riding the earlier 1st Gen MK1's for years and can tell ya, Mom Yam did you MK2 riders a great favor by giving you a bleeder to work with up there. Not that bleeding off the metering valve is that difficult but many flare nuts on that little section of connecting tube have been rounded off in the process of someone trying to bleed that high spot down... Here is vid of what us geezers had to put up with..

Concerning the sideways pics,,, I am farrrr from any form of a picture taker professional but can tell you that most of the issues I have had posting up pics end up having to do with picture size.. I put my camera on economy size,, 380 x 650 I think it is,, and all works perfect.. Get up much higher than that and funny things start happening,,, to point of not even being able to post pics. If I have pic's that are over that size, I use "Paint" to size them down and then resave them in the smaller size.. At one time I think I found I could get by with sizing the top/bottom size at 750 pixels or something like that in paint.. Bottom line Banks,, I would take a close look at what size of pics your trying to post,, first place I would check if it were me!! Here is another one of my corney vids:

Here ya go Banks,, check take a peek at this if and when ya get a second:

[Banks412]

Thanks again so much Puc! I don’t see any links to your videos you mention though. I’d love to watch them. Can you try to reattach the links?

 

Tim

[cowpuc]

Thanks again so much Puc! I don’t see any links to your videos you mention though. I’d love to watch them. Can you try to reattach the links?

 

Tim

 

Hmmm,,, not sure why that is Tim,,, I wonder if it's because you are a trial member.. I do see the the video here.. Tell you what,, if you go back to youtube and search for "for my buddy blood!! Bleeding brakes on a 83 Yamaha Puc Puc" (just copy/paste what I typed between those quotes in the youtube search) and let me know if you find it.

[cowpuc]

I just tested that copy/paste search of for my buddy blood!! Bleeding brakes on a 83 Yamaha Puc Puc on youtube and it worked fine on this end.. @Banks412, Tim give it a shot and let me know if you get to the one about brake bleeding. By the way,, you are more than welcome for the assistance, helping each other is a way of life around this club of ours,, glad to do it!!

Puc

[Banks412]

Is the screw that comes out of the rear master cylinder a ‘fill port’ for brake fluid??? I sure hope so because getting that top off the cylinder to fill and bleed the rear and front left brake looks darn near impossible.

[Marcarl]

Just to make sure I got it straight. The rear MC is below the reservoir. The reservoir is attached to the MC via a short rubber hose.Make sure the clamps are tight. On the outside of the reservoir is a 12mm nut which is the fill port. There is a rubber bellows inside the reservoir, best not to poke anything in there.

My suggestion would be to remove the reservoir and clean it before you fill it. It's recommended and not hard to do, one hose and one bolt holding it on.

[camos]

There is a rubber bellows inside the reservoir, best not to poke anything in there.

My suggestion would be to remove the reservoir and clean it before you fill it. It's recommended and not hard to do, one hose and one bolt holding it on.

My 89 has the fluid level alarm issue and I've read about the bellows in the rear MC but have never noticed it. Is this bellows supposed to be visible through the fill port?

 

@ Banks412

Suggest using some penetrating oil and a socket or box wrench the first time you loosen the filler bolt. They have been known to be seized which has contributed to breaking the reservoir. If the bolt does not loosen easily be gentle with the force. Perhaps a hammer drill will work best.

[Banks412]

I’m most likely wrong here, but I don’t seem to have both a rear MC and a reservoir. It seems to be all one unit with the fill port being just underneath the lid for what I assumed was the rear MC. Are y’all saying that’s actually the reservoir and the MC is underneath that?

[Marcarl]

The reservoir is square, has a nut\bolt on the side facing you near the top. That is the filler hole. The lid is fastened on with 2 or 4 screws. At the bottom or the square you'll find a 6 inch cloth covered rubber hose attached, and that leads to the master cylinder. Just work the rear brake pedal with you hand and watch what moves as you do, and you'll find the master cylinder.

The bellows can be seen if you remove the bolt from the reservoir and shine a small light into the hole.

[camos]

The bellows can be seen if you remove the bolt from the reservoir and shine a small light into the hole.

I guess that means the reservoir needs to be emptied in order to see the bellows. According to another thread, the bellows might be able to be lifted up to relieve the pressure on the reed switch. I say might because some tried it, gave up and jumpered the connection to the CMU.

 

Just had an additional thought: Would the bellows be at the top of the reservoir in the same way it is on the handlebar?

 

 

@ Banks412

The MC can be found at the other end of the hose coming out of the bottom of the reservoir.

 

[Prairiehammer]

I’m most likely wrong here, but I don’t seem to have both a rear MC and a reservoir. It seems to be all one unit with the fill port being just underneath the lid for what I assumed was the rear MC. Are y’all saying that’s actually the reservoir and the MC is underneath that?

 

Be very careful while attempting to remove the fill plug. It is often very tight and the boss it screws into WILL break off the reservoir if too much torque is applied to the fill plug. I recommend using two wrenches when removing the fill plug. One wrench is fitted to the boss and the other to the plug. Hold back on the boss while loosening the fill plug.

 

 

As for the brake system bleeding order, Yamaha says to do it in this order:

 

[camos]

Be very careful while attempting to remove the fill plug. It is often very tight and the boss it screws into WILL break off the reservoir if too much torque is applied to the fill plug. I recommend using two wrenches when removing the fill plug. One wrench is fitted to the boss and the other to the plug. Hold back on the boss while loosening the fill plug.

The only pic I've seen of a broken reservoir showed the break to be at the filler plug. Putting a wrench on the boss would not prevent that, perhaps a vise-grip would be better.

 

 

The pic you put up must be for a MkI since the MkII does not come with a fluid level glass. In the diagram it doesn't look like the bellows would be likely to cause the level warning issue. Any thoughts on that?

[Prairiehammer]

The only pic I've seen of a broken reservoir showed the break to be at the filler plug. Putting a wrench on the boss would not prevent that, perhaps a vise-grip would be better.

 

Indeed, the fill plug boss is what breaks off when too much torque is applied to the seized fill plug. It happened to me on my 1983.

Using an open end wrench of the correct size or an adjustable wrench, on the flat sides of the projecting fill plug boss and applying equal counter force to the torque generated while attempting to remove the plug will prevent the boss from breaking off.

An example of the broken reservoir (from my '83) here:

 

 

The pic you put up must be for a MkI since the MkII does not come with a fluid level glass.

 

Yes, the pictured master cylinder assembly with the sight glass on the reservoir is for a MKI. Some 1983 reservoirs had a ring cast into the reservoir but no sight glass. Even earlier 1983 versions were completely devoid of the sight glass ring casting (as in my 1983 reservoir pictured above).

 

But, my 1990 had a reservoir with the cast in ring for the sight glass and even the "LOWER" line.

 

I have also a picture of a European (3JT) 1990 with the sight glass.

 

 

Bottom line, any of the reservoirs will work on any of the years.

I have previously done extensive research on the rear brake master cylinder assembly. Here are my notes on the subject.

 

Keep in mind the various part numbers are for the COMPLETE rear master cylinder assembly, which includes the reservoir. Different part numbers do not necessarily reflect differences in the reservoir alone. Yamaha never assigned a part number to the reservoir only.

 

 

In the diagram it doesn't look like the bellows would be likely to cause the level warning issue. Any thoughts on that?

 

An empty reservoir may allow the bellows to descend quite aways. Look closely at the picture of my broken 1983 reservoir and you can see the bellows has extended quite low into the reservoir. But, I agree that the bellows would probably not be able to obstruct the float for the fluid level indicator. The float rides up and down on a hollow stem containing a magnetic switch. The top of the stem would likely prevent the bellows from contacting the float. Maybe.

 

A pic of the interior of the rear brake reservoir from my 1990. The rectangular white part is the float.

 

Edited October 24, 2018 by Prairiehammer
Additions and clarification.

[gaj1917]

Very interesting. Amazing it took so long to get the window. Always thought it odd that my '84 lacked one.

[camos]

Thanks for all the pix Kevin.

 

Looks like I should remove the reservoir and see if a proper cleaning will free up the float.

 

Do you, or anyone, think the level line for the non existent sight glass is actually the preferred fluid height? I have always filled the reservoir to just below the lower edge of the fill hole which is significantly higher than the level line.

[Prairiehammer]

Do you, or anyone, think the level line for the non existent sight glass is actually the preferred fluid height? I have always filled the reservoir to just below the lower edge of the fill hole which is significantly higher than the level line.

 

The level line "LOWER" is the minimum level, not the preferred level.

 

 

Looks like I should remove the reservoir and see if a proper cleaning will free up the float.

 

Not a bad idea, but you may not find a problem with the float. The switch itself may be bad (stuck open). The switch is a tiny magnetic actuated reed switch. It is not serviceable beyond replacement. And it is no longer available new. You might try applying a strong magnet to the float stem to see if the switch closes.

 

Because the FRONT brake master cylinder reservoir fluid level switch is wired in series with the REAR brake master cylinder reservoir fluid level switch, an open switch in either reservoir will illuminate the brake fluid level warning icon on the monitor. One way to test the switches and circuitry is to jumper the connectors for the reservoir switches on the wiring harness. Since the switches are normally closed (no warning), jumpering the leads will simulate closed switches. If the brake fluid level warning is still illuminated after installing the jumpers, there is either an open circuit in the wiring harness, faulty connections or a faulty CMS.

 

[camos]

The level line "LOWER" is the minimum level, not the preferred level.

That's interesting info. Looks like I have been overfilling it when setting the level just below the fillier lip.

 

Not a bad idea, but you may not find a problem with the float. The switch itself may be bad (stuck open). The switch is a tiny magnetic actuated reed switch. It is not serviceable beyond replacement. And it is no longer available new. You might try applying a strong magnet to the float stem to see if the switch closes.

 

Because the FRONT brake master cylinder reservoir fluid level switch is wired in series with the REAR brake master cylinder reservoir fluid level switch, an open switch in either reservoir will illuminate the brake fluid level warning icon on the monitor. One way to test the switches and circuitry is to jumper the connectors for the reservoir switches on the wiring harness. Since the switches are normally closed (no warning), jumpering the leads will simulate closed switches. If the brake fluid level warning is still illuminated after installing the jumpers, there is either an open circuit in the wiring harness, faulty connections or a faulty CMS.

I'll give those things a try before deciding to take out the reservoir.

 

Thanks again Kevin.

 

You are a fountain of detailed information.