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Foot brake valve leak in cab


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I am working on getting my 2004 mack vision tipper ready for rego and I am hearing and seeing air leaking out of the boot on foot brake where it goes through firewall. Its leaking in the cabin side where pedal pushes on the valve.

It leaks air when we press brake pedal lightly but seems to stop leaking if we push pedal hard. I can hear a feint leak from engine bay side when I lift little round rubber flap on brake valve but most of the air seems to leak into cab side of valve.

it’s my first truck, Is this normal of not? 

I can’t hear any leaks there except when we push brake pedal.

theres 8 ports on valve 4 up and 4 down theres a number on top of valve 5631

thanks

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I started to take pictures with my phone in recent years..  it has helped me a few times. but marking the lines is my go to approach.  I used too prick punch the fittings and the valve, so when i have it off on the bench, i can swap/replace the fittings with ease..  jojo

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older style had a couple of springs under the valve plates not hefty  just long enough to throw dirt or whatever. point is advised to wear safety glasses not only  that project == every one.   even greasing .

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On 3/13/2022 at 3:48 PM, The Nitro said:

I will order a new valve and pull this one apart afterwards just to see how it  works. Thanks for the tips.

 

one of the best teachers is yourself when taking things apart to see what makes them tick. i never stop preaching safety . 

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16 hours ago, mechohaulic said:

one of the best teachers is yourself when taking things apart to see what makes them tick. i never stop preaching safety . 

That's how I learned pretty much everything I know.  Take it apart and look.  But, you are right on the money with the safety aspect.  Always be wary of springs and things.

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"Eagles may soar, but weasels don't get sucked into jet engines."

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Posted (edited)

Picked up the new valve from freight depot yesterday and took lots of pictures of old valve plumbing and removed it from truck. Got both valves at bench vice and will swap out the fittings and try get same angles tonight after work.

Looks like brass tapered air fittings so might get some sort of thread locking goo from town before I start.

Most of the air lines had olives on them so not sure how interesting it will be with leaks at the 9 threaded fittings  and 12 air lines I had to undo to get brake valve out 

Edited by The Nitro
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4 hours ago, mrsmackpaul said:

Olives are these things for airlines, well at least thats what they are called out here

 

Paul

s-l400.jpg

once again another fact is proven . no matter how long a person does a job , there's always room for new knowledge . after 50 yrs wrenching never knew they were olives. i know plenty of times when the line wouldn't move i called the brass ferrells alot of other names.

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HAhaha, you guys. So the treddle valve job went ok but I have 1 of the short 1/2 inch hard plasic lines going up to the governor/regulator valve not playing the game and leaking air so need a couple more bits and pieces for that.

The next job on the list is the leaking tipper ram seals. I’m not trusting the single safety beam prop on one side thats on the truck so will have to make a better one before I climb up in there to pull cylinder out. 

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2 hours ago, The Nitro said:

HAhaha, you guys. So the treddle valve job went ok but I have 1 of the short 1/2 inch hard plasic lines going up to the governor/regulator valve not playing the game and leaking air so need a couple more bits and pieces for that.

The next job on the list is the leaking tipper ram seals. I’m not trusting the single safety beam prop on one side thats on the truck so will have to make a better one before I climb up in there to pull cylinder out. 

TAKE ABSOLUTELY NO CHANCES UNDER THAT BED.  I SAW A MAN DIE UNDER ONE ON AN R35 EUCLID.

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"Eagles may soar, but weasels don't get sucked into jet engines."

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Cause once you see it falling and your eyes get around to telling your brain that you need to move its too late like your only a spot of grease from now on.Please brace it up more than good.

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glenn akers

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If anyone tells you any B.S.  tell them to go away, or you go away..  I was almost cut in half by an employee of mine, we were working on a Cat V-250... older lift.  I was setting it up to replace lines and I had the forks up and was fixing a chain, to hold it up and I had long 4x4's ready to put in the channels as an extra helper, and dum dum was starting to take line clamps off and lines.. If I didnt see him, he would have possibly pulled a line that would have changed both our lives..  anyway...  jojo

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I’m planning to drill a 5ft deep hole with the post hole digger on skid steer and position the truck over hole so that the only cross beam of body is over the hole when its at 2.8 meters high. Drop air from airbag suspension and chock all the wheels and park brakes on.

Undo the top ram bolts with body fully down and attach some type of ratchet strap to top of ram that I can use to collapse ram if it wont come down itself by gravity. Raise body with ram and Cut a fresh wooden post from a box tree trunk about a ft diameter and put it down through chassis into my hole fill it in with dirt so its solid and the top of post is the right height to compliment the factory body prop thats fitted to truck already.

lower body onto post and prop and put a log across rear of chassis rails as well.  Lower ram with gravity or my pre  installed ratchet strap up on top of ram and put my skid steer forks straddling the top half of ram main body tube and sling ram to forks and lift out when rams fully down and base  unbolted.

should be able to put ram back in and raise it with pump between my forks as a guide up into truck body top mount and take the weight. Chainsaw my post out then remove factory prop last and lower body fully then get top bolts in last after its all back down.

Thats about the best way I can come up with that minimises the amount of time I need to be in there which is to tie ram to my forks and to ratchet the ram down to collapse it if needed.

I dont like the idea of a short prop at rear of body near hinge point as I have seen that rear pin fail once and a fail there would still see a guy squashed under front of body as rear would simply see saw upwards if the hinge failed and front of body would drop as its heavier.

Before I do this, anyone see something I’m missing with the plan I described?

Thanks,

 

 

 

 

 

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