Blown bushings in the rear, how can you tell??

[Jaysin]

I just got back from Sun Peaks a few days ago, and it seems to have taken its toll on my bike:P
When I pick the bike up in the rear, and put it back down, there is a bit of play in the rear suspension...I believe this is caused by blown bushings, correct??

Also, I got my bike off the back of the truck and noticed the lil knob rubber stop you put over your bleed area of your brakes, was off.....and then I noticed there was oil or osmething all over my tire??? But there was no sign of brake fluid coming out of the lil hole.....I was wondering if you had no brake fluid whatsoever, would you still have minimal stopping power?? Because it seems to me that the brakes need to be pulled in further for them to grab......

Just a concerned bike owner:(

[Bryce]

Yes, sounds like time for new bushings

the little rubber cap is just there to keep dirt out of the system, they usually fall off after a while. Unless the nut came loose, no fluid should have leaked out. Most likely the lever pulling closer to the bar is from pads wearing or from heated fluid coming out from the top. This is normal. Adjust the reach so that its comfy once again and when it gets really bad, have it bled

If you have no fluid in there or if its too low, you will have absolutely no stopping power in the brake

[Jaysin]

Thanks Bryce!

Its a brand new Bike, so I dont think the pads are gone yet:P

[corey@nsmb.com]

The only bushings on your bike are the DU's in the eyelets of your shock.

My money goes on the lower one (by the rebound knob) being worn. They are about $5 to replace, and you'lllikely just need one.

Common maintenance on FS bikes. :)

[Jaysin]

Thanks again Corey, I should just start PM'ing you when I gotsa problem:)

[XXX_er]

I bet the little allen screw on the inside of the brake lever has backed out,thats the one everybody talks about putting blue loctite on

hey did you see the drop-in crew is in town?the bus is parked at mcbike and apparently they been filming across the north

[corey@nsmb.com]

Originally posted by Bryce
Yes, sounds like time for new bushings

the little rubber cap is just there to keep dirt out of the system, they usually fall off after a while. Unless the nut came loose, no fluid should have leaked out. Most likely the lever pulling closer to the bar is from pads wearing or from heated fluid coming out from the top. This is normal. Adjust the reach so that its comfy once again and when it gets really bad, have it bled

If you have no fluid in there or if its too low, you will have absolutely no stopping power in the brake

Brakes only need bleeding if air gets in. If air gets in, it is diplacing brake fluid somewhere, which means you have a leak. Fluid doesn't go anywhere when the pads wear, it stays in the system and air stays out. (unless as I said, you have a problem).

Jayson, sounds like you need to adjust the lever to compensate for pad wear. Sun Peaks will do that.

If you have fluid on your tire and the caliper, look for the obvious first...is the bleed screw in tight? Is the caliper leaking from the pistons?

If you lose fluid, the lever will grab inconsistantly, and progresively fade as you lose more fluid. Then they will stop grabbing and you will start crashing. :)

[Bryce]

Originally posted by corey@nsmb.com
Brakes only need bleeding if air gets in. If air gets in, it is diplacing brake fluid somewhere, which means you have a leak.

What about the fluid that slowly bubbles out from the top of Hayes? I've always assumed that this was to compensate for pressure build-up when the fluid gets hot from lotsa braking. Can air then get drawn back in when everything cools down?

Personally, I don't think I've ever had a major leak but over time I can feel air getting into the system (the lever reach must be adjusted further and further out)

I've had hayes for years and there are still things that are kind of a mystery to me. Like the pistons self-adjusting and retracting. I'd like to see a diagram of the system or something

[corey@nsmb.com]

Originally posted by Bryce
What about the fluid that slowly bubbles out from the top of Hayes? I've always assumed that this was to compensate for pressure build-up when the fluid gets hot from lotsa braking. Can air then get drawn back in when everything cools down?

Personally, I don't think I've ever had a major leak but over time I can feel air getting into the system (the lever reach must be adjusted further and further out)

I've had hayes for years and there are still things that are kind of a mystery to me. Like the pistons self-adjusting and retracting. I'd like to see a diagram of the system or something

If fluid bubbles out of yours when they are being used, I'd say you have a faulty seal in the bleeding screw. It's just an o-ring. If it was over-tightened, I've seen the master cylinder body crack along the edge where the philips head bleed screw goes in.

It's pretty simple how they work. It's a master cylinder like a car, but the fluid is contained in a rubber "baloon" type bladder. As your pads wear, the pistons move out: the volume of fluid behind them is growing. The system draws fluid out of the baloon bladder to fill this space. It repeats to keep relatively consistent lever feel.

When you put new pads in, you press the pistons back into their bore. This displacec that fluid back into the rubber bladder, ready to start the process all over again.

(note: this is the Mag type brake)

I'm pretty sure the Hayes website has something that explains how they work with good diagrams too.

Let me know if you have any questions. :)

[XXX_er]

Hayes are not a closed system,they can compensate for heat,but I am not exactly sure how cuz I have never had to go into a hayes master cylinder.

grimecas are closed,I seen them lock up and have to be pushed along the flat spots on a 900meter descent

[corey@nsmb.com]

Originally posted by XXX_er
Hayes are not a closed system,they can compensate for heat,but I am not exactly sure how cuz I have never had to go into a hayes master cylinder.


Check out my blurb above.

As fluid expands, it will travel into the bladder, and not cause the brakes to lock. When it cools, it leaves the blader.

[Damage Inc.]

If you suspect that it is the bleed screw o ring inspect it carefully and you should just replace it with a new Hayes o ring. They are pretty cheap if you can find one. Those o rings have a thin wire core that maintains their shape and seal.

I've mangled an o ring up at the lever body before that was not easliy noticable. I keep rebleeding the brakes only to find more air in the system after a few cycles of the lever... 5 bleeds later I notice a little nick in the bleed screw o ring. that nick exposed the wire center when the screw was tourqued up mis-shaping the o ring and allowing air in.

Go figure eh?

[Damage Inc.]

When my fluid expands it leaves my bladder too...
:rolleyes:
Usually after my 3rd beer

[corey@nsmb.com]

Originally posted by Damage Inc.
When my fluid expands it leaves my bladder too...
:rolleyes:
Usually after my 3rd beer

Lightweight!

Don't break the seal! :lol:

[Damage Inc.]

3 Hogaardens in the authentic Hogaarden glass...

...now back to your regularly scheduled thread...

...if you read this thread wrong you might find out that he blew a seal...

Thank you, thank you. I'm here all week folks...

[yellowdogx]

Originally posted by corey@nsmb.com
If fluid bubbles out of yours when they are being used, I'd say you have a faulty seal in the bleeding screw. It's just an o-ring. If it was over-tightened, I've seen the master cylinder body crack along the edge where the philips head bleed screw goes in.

It's pretty simple how they work. It's a master cylinder like a car, but the fluid is contained in a rubber "baloon" type bladder. As your pads wear, the pistons move out: the volume of fluid behind them is growing. The system draws fluid out of the baloon bladder to fill this space. It repeats to keep relatively consistent lever feel.

When you put new pads in, you press the pistons back into their bore. This displacec that fluid back into the rubber bladder, ready to start the process all over again.

(note: this is the Mag type brake)

I'm pretty sure the Hayes website has something that explains how they work with good diagrams too.

Let me know if you have any questions. :)

What about that small hole on the rear of the lever...umm closest to the bars that is, I have a little occasinal weep comming out there. Have not noticed any loss of performance but some paint is starting to peel on the master cylinder. Whats up with this?:???:

[IFO]

Originally posted by XXX_er
Hayes are not a closed system,they can compensate for heat,but I am not exactly sure how cuz I have never had to go into a hayes master cylinder.

grimecas are closed,I seen them lock up and have to be pushed along the flat spots on a 900meter descent

WRONG....

grimeca hyrdo's are open system aswell...

the only Closed system made today is by Hope... their C2 is a closed system,...

[Joe Dick]

I think Bryce is talking about the fluid which comes out of the small horizontal slit on the back side of the lever. it seems to a some sort of a blow by to release expanded fluid due to over heating in a sealed system such as the Hayes. your car, or Shimano use a resevoir system so they have no need for this. it's normal, though I've never seen it bubble out.

Jasin, new bike, Norco I take it, unless your realy keen to do the work your self, get Adam to give a look over, it's free you know.

[Damage Inc.]

Brake fluid strips paint very well. Sounds like a small leak or a spill when bleeding.

[corey@nsmb.com]

Originally posted by yellowdogx
What about that small hole on the rear of the lever...umm closest to the bars that is, I have a little occasinal weep comming out there. Have not noticed any loss of performance but some paint is starting to peel on the master cylinder. Whats up with this?:???:

That's a "vent" for lack of a better term.

There is lube all over the bladder, a vaseline-consistency gunk that keeps things clean.

When you see moisture around there, it's more than likely a combo of this jelly stuff mixed with a bit of moisture from a wet ride.

If it's dry, it could be a tiny bit of brake fluid from weeping around the sealing edge of the bladder. It isn't what you would classify as a leak, it's more of a weeping seal, kinda like a ball joint on a car.


A simple test for a blown master cylinder is to invert the lever body, and squeeze the lever. If fluid drips out of this vent, you know you have an internal leak in the master cylinder and it's time for new parts.

[yellowdogx]

Originally posted by corey@nsmb.com
That's a "vent" for lack of a better term.

There is lube all over the bladder, a vaseline-consistency gunk that keeps things clean.

When you see moisture around there, it's more than likely a combo of this jelly stuff mixed with a bit of moisture from a wet ride.

If it's dry, it could be a tiny bit of brake fluid from weeping around the sealing edge of the bladder. It isn't what you would classify as a leak, it's more of a weeping seal, kinda like a ball joint on a car.


A simple test for a blown master cylinder is to invert the lever body, and squeeze the lever. If fluid drips out of this vent, you know you have an internal leak in the master cylinder and it's time for new parts.

Thanks!

[XXX_er]

Originally posted by IFO
WRONG....

grimeca hyrdo's are open system as well...

the only Closed system made today is by Hope... their C2 is a closed system,...

the grimeca web site sez in the HINTS section you may not be able to spread the brake pads due excess fluid in the master cylinder that will have no chance to expand in the resivoir.You may have to take the cap off the matercylinder to spread the pads or even remove some fluid ... seems kinda closed to me, you don't have to do that kinda thing with hayes

in any case they don't seem to compensate for much

[IFO]

Originally posted by XXX_er
the grimeca web site sez in the HINTS section you may not be able to spread the brake pads due excess fluid in the master cylinder that will have no chance to expand in the resivoir.You may have to take the cap off the matercylinder to spread the pads or even remove some fluid ... seems kinda closed to me, you don't have to do that kinda thing with hayes

in any case they don't seem to compensate for much

you only need to do that if you have added fluid during the course of pad wear...

i do it all the time... as my pads wear i fill the master cylinder up...

then when i replace my pads i siphon a small amount of fluid out...it works good to keep air from getting into the brakes due to low fluid level...

[just ride]

Originally posted by Damage Inc.
When my fluid expands it leaves my bladder too...
:rolleyes:
Usually after my 3rd beer

No worries, im hella tipsy after my 3rd beer, 5 or 6 (depening how much i ate that day) = me slammed.

[Aldo Nova]

corey can answer everyones biking troubles:)

[switch]

Corey's explanation is exactly how the Hayes brakes work.

When you put new pads into a Hayes caliper, push the pistons back into the bore, put in the new pads, put on wheel, place a business card between the rotor and each pad, and then pump the handle 10 to 20 times. This helps ensure the fluid that went into the calipers, from the bladder, is pushed back into the bladder. Take business cards out, and you'll have new pads and no rotor rub.

This will not work if you bled the brakes with worn pads and completely filled the bladder; in that case you'll have to drain a bit of oil.

I'd like to buy some of that "vaseline-like" lube that's used on the bladders. I think it's some kind of marine-grade grease. Anyways, the stuff is awesome, but you get such a small amount with a master cylinder kit.

[DaveM]

I've got a question. After a long run down Honeydrop on Sunpeaks, my Hayes Mag lever came all the way in to the grip, with no braking power at all, forcing me to ditch it into the rhubarb. After a couple of minutes of squeezing the lever, all returned to normal. Overheated? It happened a couple of times on long steep runs. If it did overheat, should I change the fluid? It seems ok now.

[IFO]

sounds like u boiled the fluid... assuming it wasnt your lever reach screw that had simply backed out...

but if u didnt have to adjust it to get your brakes back, then i'd say it was overheated brakes...

its no big deal... just wait a few minutes to allow the fluid to cool down...

[Jaysin]

Originally posted by davet
I've got a question. After a long run down Honeydrop on Sunpeaks, my Hayes Mag lever came all the way in to the grip, with no braking power at all, forcing me to ditch it into the rhubarb. After a couple of minutes of squeezing the lever, all returned to normal. Overheated? It happened a couple of times on long steep runs. If it did overheat, should I change the fluid? It seems ok now.

I can see why it happened on Honey Drop.....that trail is awesome!!!! Kaboom-Honeydrop-Arm Pump:)

[Painting_of_Rebelion]

Originally posted by Jaysin
I just got back from Sun Peaks a few days ago, and it seems to have taken its toll on my bike:P
When I pick the bike up in the rear, and put it back down, there is a bit of play in the rear suspension...I believe this is caused by blown bushings, correct??

Also, I got my bike off the back of the truck and noticed the lil knob rubber stop you put over your bleed area of your brakes, was off.....and then I noticed there was oil or osmething all over my tire??? But there was no sign of brake fluid coming out of the lil hole.....I was wondering if you had no brake fluid whatsoever, would you still have minimal stopping power?? Because it seems to me that the brakes need to be pulled in further for them to grab......

Just a concerned bike owner:( man I have the same problem, when I lift the back end up so it relives preassure on the shockand then barely set it down, there's like a clunking/notchy feel to the rear end...

[.Robinson]

the little rubber cap isnt keeping your fluid in your brake line!

[switch]

Originally posted by *The RiPPer*
the little rubber cap isnt keeping your fluid in your brake line!

My rubber caps fell off! :eek:

[derwood]

My dog blew a rear bushing once when he ate a whole bag of dry pasta