HELP.. Hayes master cylinder ???- Mtbr.com
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  1. #1
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    HELP.. Hayes master cylinder ???

    People that have not fooled around with their master cylinder, dont bother reading, you wont know wtf is going on.

    Ok so heres the story, my front hayes mag lever was being a little sticky and acting up and making sticky squeek sounds, so I decided I would pull apart the master cylinder and clean it all up and make it fresh. I took it apart fine, everything was going good, and I re-installed everying and the hose and everything was perfectly ready for a bleed. As I was bleeding it, I noticed that there was NO fluid coming out through the little phillips screw hole on the master cylinder bladder retainer, and all of my fluid was just leaking out of where my bleeding hose was attached to the caliper bleeder. Thinking WTF, I took the hose off of the master cylinder, and pushed some fluid through the hose to make sure that it was going through the hose, and it was. So I put it all back together without the lever body and bladder so I could see what was happening, and tried again, same thing happened, the fluid wouldnt go through the master cylinder and bladder and come out the hole at the top. So I took apart the master cylinder again, took out the piston and made sure I had the spring and spring guide placed in there fine, and put it all back together perfectly again (snap rings are a b!tch without a snap ring tool). Looking at the cartridge, I see that there is a series of holes for the fluid to flow through, there is 3 miniscule ones, and one lager one behind those, that looks like that is where the fluid from bleeding should come out and fill the bladder and burst out the hole. PROBLEM! ... The piston in the cartridge is in the way of all 4 of these holes!, so there is no possible way that fluid could come through the cartridge and out the hole(s) to fill the bladder and complete bleeding, because the jesus piston wont let it. So wtf am I doing wrong? How can I make the piston so that its out of the way of the holes? to my understanding there is no possible way to do so. BTW, I am using the 2000-2002 version master cylinder, with the 2.5mm push rod. I also have the 2003 version, with the 2mm push rod, but I have no push rod (due to rounding of the allen key insert, and seize of the adjuster bushing, so I grinded it off)
    Dont know what you can do to help, but please give suggestions, I will try anything, cant get much worse...
    The only way I think may be possible is to put the newer shorter sytle piston in the old style cartridge, because the old style cartridge has the holes further down closer to the hose connection, but this isnt a good idea due to where the spring sits.
    Dont worry about being confusing, just use the correct termonology and I will understand you.
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  2. #2
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    Have you tryed to remove the piston from the cylinder tube?

  3. #3
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    Quote Originally Posted by dogonfr
    Have you tryed to remove the piston from the cylinder tube?
    Yeah but when you go to bleed it, its supposed to be assembled.... And the piston is in the way of the holes, disabling the flow of the fluid through the holes....
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  4. #4
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    So you took the piston out of the cylinder then reassembled it but the piston is stuck down & wont come up?

    http://www.hayesdiscbrake.com/pdf/Ma...ildEnglish.pdf

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    Do you have the cylinder with a flat on the front of the master? If you do you cant get cylinders for them anymore.
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  6. #6
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    Quote Originally Posted by dogonfr
    So you took the piston out of the cylinder then reassembled it but the piston is stuck down & wont come up?

    http://www.hayesdiscbrake.com/pdf/Ma...ildEnglish.pdf
    No, its the gayest thing ever, the piston is in the RIGHT place that it is supposed to be, close as possible to the washer inside of the snap ring, but it still covers the holes, I dont understand it one bit why its like that, but I think something is wrong.

    Flat on the front of the master? what do you mean? the master cylinder body is interchangeable with the current hayes mag master cylinder body, the only difference of the years is the push rod size, and the internal spring setup & Piston.
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  7. #7
    TNC
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    Actually you can get the later master cylinder cart to fit the older housing. I've got a set of antique '99 Hayes that I had to replace a cart in, and like you I stated, l couldn't find a replacement. Since I have two other later model Hayes sets, I went ahead and obtained the later master cylinder cart. After a bit of fiddling, some grinding, and creative spacing in the nose of the old housing, I was able to get it to work. It's been over a year, maybe as long as two, since I did this, and when the other side of this antique pair needs fixing, I'll have to figure out what I did and repeat the process. I can't remember exactly what wound up working because my memory is not that good for that long a period...sorry. This update worked fine, and the brakes are as powerful as ever. Jake seems fairly proficient in a mechanical sense, so I think he might be able to get a later cart to work.

  8. #8
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    In the pic above the front of the master is is on the trash lid, if the flat is on that part of the master there is no more replacement cylinders. I had to buy new masters to replace old ones. The parts cataloge list a universal cylinder rebuild kit but it does not fit that model.

  9. #9
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    Quote Originally Posted by TNC
    Actually you can get the later master cylinder cart to fit the older housing. I've got a set of antique '99 Hayes that I had to replace a cart in, and like you I stated, l couldn't find a replacement. Since I have two other later model Hayes sets, I went ahead and obtained the later master cylinder cart. After a bit of fiddling, some grinding, and creative spacing in the nose of the old housing, I was able to get it to work. It's been over a year, maybe as long as two, since I did this, and when the other side of this antique pair needs fixing, I'll have to figure out what I did and repeat the process. I can't remember exactly what wound up working because my memory is not that good for that long a period...sorry. This update worked fine, and the brakes are as powerful as ever. Jake seems fairly proficient in a mechanical sense, so I think he might be able to get a later cart to work.
    You have more patients than me. I tryed & the flat on blader would ride up the outside of the master. I dont recall all the different ways i tryed either but replaceing assembly turned out alot easier.

  10. #10
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    -The picture of the black lever body is the SAME shape as the TWO lever bodys I have, one is grey (2000 mag DH model) and one is black (current 2004 DH model)
    -I have two complete master cylinders with bodys...
    -See the note says that 2000-2002 DH models use 2.5mm allen key for the push rod, this push rod is the one PICTURED in the diagram of the master cylinder, along with that style of MC piston, comes that push rod... The mc piston for this 2.5mm push rod is plastic.
    -When you fit this MC piston into that pictured cartridge, it all snaps in with the springs and all (note that 2000-2002 models have spring guide!) and the MC piston when fitted in and ready to go, actually BLOCKS the holes on the cartridge, which allow the fluid WHILE bleeding, to pass through these holes, and into the bladder which covers the cartridge, and out into the bladder retainer (also plastic) and out through the hole that is covered by a tiny phillips screwdriver bolt. This is to fill the bladder with fluid so that you can use your brake succesfully, but I have a PROBLEM, those holes are blocked by the MC piston! so there is no way that fluid can go through them to complete the bleed!

    -I also have the newer style master cylinder, which is a bit different than the one pictured in the diagram. The MC piston is actually shorter, and made of metal. It does not use a spring guide, however, it does use the smaller sized push rod, at 2mm, instead of 2.5mm
    -And I dont even have the 2mm pushrod becuase I grinded it in half so I could take apart the master cylinder, I grinded it because the adjuster bushing was SEIZED on the push rod, and also the allen insert was rounded and impossible to use sucessfully
    -So I cant just use the smaller MC piston (which would free the holes) with the large pushrod, becuase it doesnt fit.
    -ALSO, the cartridges are DIFFERENT The 2000-2002 cartridge is setup to use the skinny spring that sets up with the spring guide. This older cartrige has those 4 holes further down away from the push rod (a good thing in my case) So I can use this cartridge, with the BIG spring along with the smaller new MC piston. But my problem is, I dont know how I am going to be able to get a 2mm push rod!
    - So this leaves me with, how can I setup the whole master cylinder setup (the one pictured) so that those holes will be free? It has been done before to this exact brake, because it was setup before I put my hands on it, the question is, how?
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    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  11. #11
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    aha, found a picture of 2004 model Piston and spring and pushrod!
    This is what the piston looks like, notice how it is short, so it will not block the holes, but it needs to be used with that 2mm pushrod, which I dont have... That spring does not use a spring guide, so it is wide enough to fit in the old style cartridge without problems...
    So that setup you see in this picture, would be 100% successful if I could get the 2mm pushrod, which I am still looking for.

    But I might not be able to get this 2mm rod, and if I do it wont be for a while, thats why I need help to find out how to use the plastic big MC piston, without blocking the holes
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    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  12. #12
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    Possibly the first seal is swolen or the retaining washer is to thick last the piston is not going all the way up to the retaining washer. Couple options i came up with sand the top of the piston so that it hits the washer later causing the piston seal to go above the hole. Other idea is to elongate the hole to clear the piston seal, if you do this be shure to polish the cylinder so it does'nt cut the seal. The seal should be just above the hole so when you squeez the lever it closes the hole pushing the fluid to the hose. The other pistion wont work.
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  13. #13
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    If you order the rebuild kit you get the one on the left. As far as i know its the only one available. Hopefully TNC will remember what he did to install it to his, i may need that trick myself later since i still have 2 olde school cylinders in opperation still.

  14. #14
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    Quote Originally Posted by dogonfr
    If you order the rebuild kit you get the one on the left. As far as i know its the only one available. Hopefully TNC will remember what he did to install it to his, i may need that trick myself later since i still have 2 olde school cylinders in opperation still.

    The one on the left, complete - Hayes Part # MC98-16345 should be ~40-45$ Includes everything but the lever body and lever.. (Reservoir, complete MC with pushrod assembled, nut, ham on rye with Dijon...

    For the 02+ mags I believe - I dont think it fits older bodies properly. Has the flat guide edge. Def better than the plastic MC, but has the wandering pivot - so make sure you get the new pivs with the nylock so your adjustments stay put.

  15. #15
    TNC
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    Hey Dog...

    Quote Originally Posted by dogonfr
    If you order the rebuild kit you get the one on the left. As far as i know its the only one available. Hopefully TNC will remember what he did to install it to his, i may need that trick myself later since i still have 2 olde school cylinders in opperation still.
    I went out to the shop to look at my '99 conversion setup, and a couple of things did come to mind. In looking at this pic, you can see where the slot portion of the newer master cylinder doesn't ride in the lever body slot like the original. This had no bearing on operation or performance. I do recall having to file or grind that slot on the lever body toward the nose of the body so that the new cart would fit into the old body an appropriate distance. I also had to do something to the inner nose of the body or the cart to get them to mesh properly. There's a notch or something in the nose of the body that wasn't a perfect fit to the new cart...I think. I may have had to do even more, but this is all that comes to mind now. I think I also recall something about having to be somewhat judicious in how I tightened the hose hardware because I didn't have the newer cart "locked" into a slot or groove as well as it was in its OEM condition. This brake has worked flawlessly with no problems. Too much cheap tequila since I installed this cart has killed too many brain cells for me to be sure now on all the mods I had to do.
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  16. #16
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    Thanks TNC, the filing of the body so the blader tab fits better is a key point. You are correct about being carefull tightening the hose to cylinder because it will spin inside the body if not carefull. I will store this in my beer brain.

  17. #17
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    Ok I went to a different LBS today, and completely lucked out, they had 2mm pushrods with the adjuster busings, sweet. So I got the pushrod and hooked the new style mc piston and spring to the old style cartidge, thinking the holes were FREE and it would all work, so I got it all setup and bled it, but when I pushed on the lever, the pistons in the caliper barely moved, this was due to that LARGE hole being over exposed, making the fluid in the master cylinder go into the bladder as opposed to down through the hose. So I took it all apart again, and placed that new MC piston into the new style cartridge, seeing that the big hole was covered, I thought what the hell maybe it will come around, so I proceeded with the bleed. It bled normal, and is all setup now and my brake is ready. The bleed sucked, but oh well. I did manage to get fluid in the little gaps between the caliper piston and the caliper body, which sucks but isnt a big deal, I just have to watch it.
    So I dont need anymore help, but thanks for your care and suggestions.

    oh and picked up some sick smith sunglasses too.
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  18. #18
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    wtf

    Ok not only a bad bleed, possibly a terrible one, or something else f*cked up?
    When I sit on the bike and dont roll, and pull the lever, it feels normal... hell a little spongy becuase of a bad bleed, but non the less normal.
    When the wheel turns and I hold the brake on (or just roll and brake, or try to stop slowly) the f*cking lever comes closer and closer to the bar as I keep the brake on, and then when I let go, and re apply brake while slowing down, it starts over at the original starting position, and then if I hold it while the wheel is moving, it repeats, coming closer and closer to the bar as I keep the brake on.
    Wtf is going on? Is there like mega amounts of air in the system or bladder? Is the piston I just put in have a broken seal --the primary one, and then the fluid leaks through and stops at the secondary seal and then leaks through the holes in the cartridge and into the bladder?
    Has anyone experienced this, if so what did you do to fix it? I really dont want to take apart the whole mc again
    I will try a bleed tomorrow, if that helps I will let you know...
    This is the most unexpected thing I thought would happen
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  19. #19
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    Can you post a pic or 2 of the setup?

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    Quote Originally Posted by dogonfr
    Can you post a pic or 2 of the setup?
    Do you mean the setup as it is on my bike right now? or the internals of the MC setup?
    Right now it looks like a 2004 setup hayes g2 mag, black, with BFL levers
    The master cylinder is using all of the latest mag parts (not ti though, lol)

    My rear brake is butter and needs no work, but the front is a different story
    tell me what you want pics of, might take a while because this computer does not have a USB port, so I have to go down the road to do pics.
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  21. #21
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    just a pic of the set up like TNC did & 1 of the lever/push rod/dust cover side type pic from behind the lever.

  22. #22
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    Quote Originally Posted by dogonfr
    just a pic of the set up like TNC did & 1 of the lever/push rod/dust cover side type pic from behind the lever.
    There I just took a whole bunch, including the ones you requested...
    Post them up tomorrow

    I love my bike
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  23. #23
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    sounds like youve got some air in them thar lines...\

    keep a bleedin!!

  24. #24
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    Cant be to woried about the brakes, im a riding cuz my brakes work.

  25. #25
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    Ok I just bled it 2 times, not much different... Still comes into the bar when I apply little pressure..
    Keep bleeding? Im getting low on fluid
    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

  26. #26
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    Pics here

    heres the pics you wanted to see, and heres the OLD master cylinder setup, I had to grind off the end of the cartrige because the 13mm bolt stripped and got stuck lol
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    Jake
    Yeti 303 WC 25th

    Quote Originally Posted by Dwight Moody
    Didn't you read the sticker on that shock? It said not to do whatever you did.

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