kenworth 2001 t300 air gauge issue

[2xR]

A leaky, emergency side (supply) glad hand grommet will cause a drop in pressure like you describe. When you park the truck you probably pull the trailer valve, thus cutting off the supply, thus stopping the leak. You wouldn't hear it.

Park on level ground, chock the wheels, then release all the brakes and have a listen.

Also, air bags flexing and equalizing will release air. That could be occurring and the regulator isn't telling the compressor to make more air until it falls to 90psi. Not unusual.

I don't sweat 90psi as long as it builds back up and don't go lower.

My truck will pull, usually to the right, if I have to get on the binders hard. The condition usually occurs about the time I need to adjust the brakes. An adjustment corrects the condition.

 

[IdriveT300]

the truck is a tanker we dont have tail altho the lines and leave for it is still there so that could be my leak the truck will hold air over night but only about 50psi so i can adjust the adjuster on my truck and it will not hurt anything ?

 

[SilverSurfer]

That's mainly an indicator you definitely have a leak. A truck should hold 120psi for several days.

-ss-

 

[IdriveT300]

ok i got time to get it looked at i had my dad come show me something i guess the old man is still good for something.he thinks it the drier and also said my rear brakes are about to cam over and i need to get new pads asap dose this sound right

 

[SilverSurfer]

As I commented earlier in the thread...I, too, believe the dryer may be the culprit to the air problem. As to the the s-cam ready to cam over because of brake shoe wear...this is a situation which would exaserbate any minor alignment issues. The drive brakes not operating properly will cause the vehicle to pull to one side or the other. This is mainly due to the steer brakes handling all the vehicle weight to stop.

Definitely pursue the air leak...but get your drive's brake shoes replaced before you chase down any alignment issues. You may find the pulling disappear when the proper braking from the drivers is corrected.

-ss-

 

[2xR]

^^^^^^^^^^^^^^^^^^^^^^^
Ditto what he said....

 

[IdriveT300]

tomarrow the truck is going in to get the drier service.we plan on doing the pads our selfs i guess the truck had a aligment about 20k ago

 

[IdriveT300]

after looking at the rear pads some more there looks to be about 5/16" on the driver side and about 3/8" on the passenger side left. Is there anywhere that I can get a manual for the air brakes for the t300

 

[SilverSurfer]

Not sure how to get a manual for your specific truck, but here's an "air brakes manual" which should provide enough information for you to acquire a good understanding of the system and components involved.
http://www.gnb.ca/0276/vehicle/pdf/ab_manual-e.pdf

You're shoes are just about at the limit (1/4 inch.) You should definitely replace them now while your down dealing with this. I wouldn't doubt you have a glazing - possibly cracking - problem with the shoes.

-ss-

 

[IdriveT300]

truck heads to the shlop in about 3 hours to get the drier fixxed ill let youll know what that dose im also picking up the brake shoes and a air cleaner.tonight when i get the truck back i plan to change the oil i have 55gl drom of 15w40 and a new filter the t300 take around 11.5gl for a oil filter change right? i also need to grease the truck

 

[IdriveT300]

well i guess i lied i was told i have to drive the truck tell something break or something gose wrong i think its time to look for a new job

 

[Mike]

well i guess i lied i was told i have to drive the truck tell something break or something gose wrong i think its time to look for a new job

Is this not your truck?

 

[IdriveT300]

its my truck to drive i guess now and im "1/3" owner in the company but i have no say what so ever it seems like so i would say no its not my truck im just the drive is how it seems

 

[SilverSurfer]

Well T300...there is something you could do besides looking for another job. Although it may result in the same outcome...lol.

Do a post trip report. Report the problems which need repair before you drive the truck. Federal regulations require this report, and company's must correct the problems before that truck is allowed to be put into service. And if the company puts that truck into service before repairs are made...whether you're the driver, or someone else...there's hell to pay. (lol)

I'm not saying you must follow this advice. But the right thing to do is just that if they are not going to take care of the problem first before asking you to get behind the wheel. You've identified a serious mechanical problem which could result in someone getting hurt.

-ss-

 

[IdriveT300]

yea it puts me in a shitty place as its family owned so im not resure what do to right now

 

[SilverSurfer]

Now that's a tough one. Definitely in between a rock and a hard place. I know how I would handle this situation, but I'm extremely uncomfortable with giving advice on family matters...especially in regards to family business. I will share with ya what my dad shared with me many, many years ago. There comes a day when a young man must act as a man according to his principles and morals. I will also say this...it did take me many years before I truly understood what he was saying.

I wish ya well on your predicament, and hope all works out. And if there's anything I can help with...don't hesitate to ask...if I'm able to help - I'm more than willing to help.

-ss-

 

[IdriveT300]

thanks its nice to know there someone there if i need to keep from going nuts.I liked the job I drive a 2500g tanker about 75miles around trip everyother day.i start at the shop pump on a load and drive to the dump and on load it then that to the shop takes about 3hours so most of the time im off work by 1. I feel that i make pertty good money been that im 19.I clear 450 a week.the main part of not fighting with them for me is that i know i cant not find money like that starting any other job also i have started to like driving and been around the bigger trucks i have no idea i dont want to hurt any one or hurt or kill my self but at the same time i dont like to piss people off then agin theres a time when i need to stand up for what is right/self thing to think about I have alot to go over

 

[IdriveT300]

i got the truck back from the shop they put a new drier on and it fixxed my leak still need brake peds tho

 

[SilverSurfer]

Good to hear the air leak is fixed. As for the brake shoes...technically they're within specs. 1/4" is the limit before you must replace them. So here's where you must decide whether you run a few loads to generate some income or not. If you decide to run...try to stay in lanes with no heavy grades, and pay extra attention to your brakes adjustment and shoe depth. Basically check 'em everytime before you start out.

-ss-

 

[mfx]

It could be in the dryer. The release valve may need replacing.

When you do a leak test on the system...if you find no leaking, pursue the cut-on/cut-off valve in the compressor feed line and the release valve in the dryer.

The reason I'm pointing out the release valve in the dryer as the culprit...is that valve is activated periodically. If it doesn't properly close, the system will continue to drain until the compressor cuts-in. And generally if you don't have a tank leak the gauge would rise and fall consistently without any delay between the cut-in and cut-out compressor controls only if you have a release valve or cut-in/cut-out control problem.

As to what to do if the pressure should drop below 90psi...get your a$$ stopped as quick as safely possible. Around 60psi the emergency brakes will activate, and you may find yourself skidding down the road...and this is where the potential for a jack-knife becomes very likely.

-ss-

Very good advice.

I had the same problem on a 96 Freightliner which turned out to be the release valve on the air dryer. I live and operate my transport company in Montreal were the temperature can fall quite low and this was when the problem most likely occurred. The release valve would get stuck open with the freezing cold and moisture caused in the air system from the raise and fall of the air temperature.

You didn't mention were you operate out of, so I'm just throwing it out there.