Discussion:
Clark GCX25 - can't bleed the brake

this GX230-0235-9246 came in with no brakes. figured the master cyl. is bad.
they place the master cylinders at an awkward space behind the steer column. spent almost 1/2 a day to re/re a new one.
then tried all day to bleed it. still the same. anyone get any idea what went wrong?
  • Posted 25 Apr 2009 00:35
  • By hellokitty
  • joined 11 Mar'09 - 86 messages
  • Ontario, Canada
Showing items 1 - 17 of 17 results.
Aftermarket wheel cylinders, had them leak while bleeding the brakes
  • Posted 6 Sep 2017 06:57
  • By towmotor
  • joined 19 Feb'07 - 360 messages
  • Ontario, Canada
I found the bleeder screw hiding under the line. I can't seem to get any pressure on the brake side. I bled the inch side and then the brake side and I can't seem to get enough pressure. I have good fluid to the wheel cylinders but only limited pressure and hardly no stop at all....
Also why is it that when I drive and then reverse it feels like brakes are dragging. I inspected the brakes before I found the master cylinders leaking and everything seemed to be good there.
THanks
  • Posted 25 Aug 2017 01:15
  • By BigEasy73
  • joined 24 Aug'17 - 3 messages
  • Louisiana, United States
I found the bleeder screw hiding under the line. I can't seem to get any pressure on the brake side. I bled the inch side and then the brake side and I can't seem to get enough pressure. I have good fluid to the wheel cylinders but only limited pressure and hardly no stop at all....
Also why is it that when I drive and then reverse it feels like brakes are dragging. I inspected the brakes before I found the master cylinders leaking and everything seemed to be good there.
THanks
  • Posted 25 Aug 2017 01:15
  • By BigEasy73
  • joined 24 Aug'17 - 3 messages
  • Louisiana, United States
WHere do you bleed the Clutch master cylinder at? The inching valve or on the block
  • Posted 24 Aug 2017 23:36
  • By BigEasy73
  • joined 24 Aug'17 - 3 messages
  • Louisiana, United States
I use to use an mustard plastic bottle with a rubber hose connected to it. Fill the bottle up with brake fl. and open one bleeder at the wheel cyl. and connect the hose to the bleeder. Squeeze the bottle, forching the brake fl. back up through the system and you will see air coming up into the resviour. Close the bleeder and take off the hose. Do both sides a couple of times and you should have a good brake pedal.
  • Posted 17 Dec 2011 11:15
  • By stephen_j
  • joined 4 Nov'11 - 34 messages
  • Indiana, United States
hello all, my 2cents, alway keep spare cap on hand to adapt to radiator pressure tester w/ gauge. makes just the right amount of air. once used shop blow gun and it got away from me and split the hi quality reservuor,what a mess. mike a
  • Posted 3 May 2009 11:07
  • By aloris
  • joined 31 Jul'08 - 16 messages
  • New York, United States
Thanks all of you. Very good advices and suggestions.
I opened the wheels, one wheel cyl. leaking too, so I changed it.
Then with a power bleeder, done quickly. This thing is hard to bleed manually.
  • Posted 30 Apr 2009 00:35
  • By hellokitty
  • joined 11 Mar'09 - 86 messages
  • Ontario, Canada
my best results have been with compressed air also. Bleed the air out with a vac pump or by running a line from the bleed screw back to the M/C. and pump the pedal a few times. Put the cap back on the reservoir and blow about 10psi into it. Pedal should be tight at this point. Stop there! If you open the bleeder again you will lose pressure. I spent a day and a half trying to bleed my first one and it only took two minutes once a old timer showed me that trick.
  • Posted 29 Apr 2009 00:46
  • Modified 29 Apr 2009 00:47 by poster
  • By gshort
  • joined 29 Apr'09 - 10 messages
  • North Carolina, United States
Glad to see i am not the only one that has lost sleep on this one. I have found only one thing that works. If you attach the brake lines to the master cylinder and then remove the cylinder from the frame and bend the line so the unit is horizontal NOT Vertical. grab a screw driver and pump the little air bubble out. It won't bleed properly in the vertical position. If the reservoir is loosing fluid but you have no visual leaks it might be leaking inside the trucks trans axle. lets us know if any of our suggestions work
  • Posted 28 Apr 2009 22:24
  • By Prentice
  • joined 25 Jun'08 - 600 messages
  • Ontario, Canada
bleed the inching valve 1st (even if you didnt touch that side)
then bleed the wheels

i used to get the same issue a lot
never even thought of touching the inching (since i didnt touch it in the 1st place)
but apparently when the pressure is lost on the service side
the inching master loses some sort of equilibrium and you have to reset (bleed) the pressure on that side before moving back to the service side

pssed me off whn i realized what the stupid issue was lol
i tried every trick above and none really work
you might get ehh pressure back but the inching is sloppy (internally) and you wont get a good service brake pedal
  • Posted 28 Apr 2009 12:02
  • Modified 28 Apr 2009 12:22 by poster
  • By justinm
  • joined 13 Apr'06 - 604 messages
  • New York, United States
New York, New York its a heluva town..you know that The Bronx is up..and I'm Brooklyn down
try jacking one side up then bleed then got to other side
  • Posted 28 Apr 2009 07:46
  • By rich_k
  • joined 30 Oct'07 - 108 messages
  • Ontario, Canada
I have found reverse bleeding to be the best way to bleed most clark brake systems. I do it similar to the way that mrfixit describes, also bouncing the pedal, but not full stroking it, while reverse bleeding helps too.
  • Posted 25 Apr 2009 14:54
  • By fixitandy
  • joined 23 Mar'09 - 81 messages
  • Pennsylvania, United States
I take a squirt type oil squirt gun thingy with a piece of hose attached and fill it with brake fluid, hook it to a bleeder and start pumping. It will push the air right up and out to the reservoir. Don't touch the petal. Who ever designed the brakes on those things had to have failed engineering school.
  • Posted 25 Apr 2009 10:50
  • Modified 25 Apr 2009 10:50 by poster
  • By mrfixit
  • joined 11 Dec'08 - 1,434 messages
  • New York, United States
AFTER C500 TRUCKS......MACHINES ARE JUST NOT UP TO SCRATCH ,,JUST MY 2 CENTS
  • Posted 25 Apr 2009 08:03
  • By DAMO
  • joined 9 Jan'07 - 196 messages
  • DUBLIN, Ireland
Hello I had this problem many times fill the reservoir screw the cap on open one of the bleed screws then use a very low pressure air line over the small vent hole in cap forcing the fluid out then do same on other wheel. Works every time.
  • Posted 25 Apr 2009 07:41
  • By combar
  • joined 1 Jun'08 - 11 messages
  • irish, Ireland
we already tried to reverse bleed it.
could bleed 1 stroke then the cyl. lost pressure right away.
don't notice any leaks along the system.
would wheel cyl. cause this problem?
  • Posted 25 Apr 2009 05:01
  • By hellokitty
  • joined 11 Mar'09 - 86 messages
  • Ontario, Canada
Yah, they are wicked hard to bleed, by design.

You can reverse bleed them, with either a pressure or vaccumn setup.

In the field, I found that you can get the pedal to pump up, by quickly pumping the pedal (~1/4 of the full stroke). Once the pedal comes up, you can bleed 1 stroke, then you have to pump them up again.

Hope this helps...
  • Posted 25 Apr 2009 00:56
  • By mike_n
  • joined 11 Feb'06 - 138 messages
  • Alberta, Canada

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Maxlion FD30
Hangzhou, China
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Braeside, Melbourne, Victoria, Australia
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March 4-5, 2026 - Detroit, Michigan, United States
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