Help identify so then I can search. Pictures provided

[sepudo]

Hi all,
Bought a brand spanking used bus and have been reading about the 3126 engine and learning lots on my free time... I crawled under the bus and found some parts that I have no clue what they are.

I wanted to see if you could help identify them so I can then search the forum for further questions I may have regarding them. It's kinda hard to search for answers when I don't even know what keywords to search for.

Many thanks in advance and happy 2020 to everyone!

[banman]

Originally Posted by sepudo

Hi all,
Bought a brand spanking used bus and have been reading about the 3126 engine and learning lots on my free time... I crawled under the bus and found some parts that I have no clue what they are.

I wanted to see if you could help identify them so I can then search the forum for further questions I may have regarding them. It's kinda hard to search for answers when I don't even know what keywords to search for.

Many thanks in advance and happy 2020 to everyone!

I like games! Guess this part is a favorite -- but you gotta through us a bone here! Can you take some pix of the parts you're wondering about and post them?

[sepudo]

Some photos
1) I believe it's another air tank as I already identified one right behind the battery box on the driver's side. Not sure why there would be 2

2) I understand the white unit is a fuel filter. Not sure why it would have an open/close valve right by it going to the engine (perhaps a pretty cool anti theft, lol)

3)very slight wetness in this area which leads to the transmission. (I want to clean it up and see if it's actually from there or if it's from higher front in the engine and dripping down the line to this spot)

Thanks in advance

[Kubla]

air tank with auto bleeder on it
water drain on fuel filter/water separator

tranny cooler lines. go to cooler built into the radiator

[FamilyCircus]

Air brake systems require a primary and a secondary air tank

Thats a water separator, the petcock is to drain out the captured water.

I wouldn't worry too much about that leak, all engines leak its when there is an active drip that you need to worry about.

[sepudo]

Originally Posted by FamilyCircus

Air brake systems require a primary and a secondary air tank

Thats a water separator, the petcock is to drain out the captured water.

I wouldn't worry too much about that leak, all engines leak its when there is an active drip that you need to worry about.

Air brakes!? I had no clue I had air brakes. I just thought it had air suspension for the driver seat. No wonder the brakes stop so great. One question regarding that now, when I first start the bus Which already has the parking brake button pulled do I need to depress the brake as I crank the bus? Hi have noticed in my 2 previous times that as soon as I start the bus the compressors kick in

To clarify is the petcock the valve with a yellow handle? If not what is the petcock and what is the yellow valve?

I was not aware that all engines leak and the last thing I would want would be catastrophic failure when I'm out in the future boondocking in my future tiny house. Thank you so much for chiming in

[o1marc]

Originally Posted by sepudo

Air brakes!? I had no clue I had air brakes. I just thought it had air suspension for the driver seat. No wonder the brakes stop so great. One question regarding that now, when I first start the bus Which already has the parking brake button pulled do I need to depress the brake as I crank the bus? Hi have noticed in my 2 previous times that as soon as I start the bus the compressors kick in

To clarify is the petcock the valve with a yellow handle? If not what is the petcock and what is the yellow valve?

I was not aware that all engines leak and the last thing I would want would be catastrophic failure when I'm out in the future boondocking in my future tiny house. Thank you so much for chiming in

When you start your bus for the first time, if the brake pressure is not built up you will not be able to release the parking brake. Bus will probably not start if it's not in neutral. When you start it thew compressors will start filling the tank until it has more than 60psi before the brakes will release. It will want to maintain around 110-120psi while running.Touching the brakes during this start up will make no difference.
Some will have a petcock to drain the tanks, some like mine have a pull cord that can be accessed from the side of the bus to pull that releases the water. Drain them daily.

[FamilyCircus]

Air brakes on modern vehicles such as our buses use a heavy spring to apply the brakes on the rear axle and use air pressure to actually release the brakes. On the front axle they use air to apply the brakes, and no spring to directly release the air diaphragm, just a spring on the brake shoes. This is a safety design to apply the brakes is you loose air pressure but you dont have front brake application.

The petcock is the little ball valve at the bottom of the filter, it lets you drain any trapped water and also inspect fuel quality should you have a driveability issue.

As for the oil leak, most diesel engine will leak some and its a good habit to always check the oil every day that you drive before driving away and when fueling, this is just a recommendation.

[Brad_SwiftFur]

Originally Posted by Kubla

air tank with auto bleeder on it

Originally Posted by FamilyCircus

Air brake systems require a primary and a secondary air tank

Originally Posted by sepudo

Air brakes!? I had no clue I had air brakes. I just thought it had air suspension for the driver seat. No wonder the brakes stop so great. One question regarding that now, when I first start the bus Which already has the parking brake button pulled do I need to depress the brake as I crank the bus? Hi have noticed in my 2 previous times that as soon as I start the bus the compressors kick in

Hang on. Is that a driveshaft parking brake I see? That would be a clue for hydraulic brakes. Is your parking brake a lever or an air knob? Under the hood, is there a master cylinder in which there should be brake fluid? (Air brake systems will not have this) Most air brakes will say so on the brake pedal and usually have very little pedal travel.


In photo 3, in the "background" I see what looks like a brake line and it doesn't look like a thick air line, it looks like a somewhat thinner hydraulic line.

To clarify is the petcock the valve with a yellow handle? If not what is the petcock and what is the yellow valve?

No, the petcock is basically a "drain" when unscrewed. The yellow handle is a basic on/off valve, likely to help prevent the fuel system losing (much) prime when replacing the fuel filter.

[sepudo]

Originally Posted by Brad_SwiftFur

Hang on. Is that a driveshaft parking brake I see? That would be a clue for hydraulic brakes. Is your parking brake a lever or an air knob? Under the hood, is there a master cylinder in which there should be brake fluid? (Air brake systems will not have this) Most air brakes will say so on the brake pedal and usually have very little pedal travel.





No, the petcock is basically a "drain" when unscrewed. The yellow handle is a basic on/off valve, likely to help prevent the fuel system losing (much) prime when replacing the fuel filter.

Under the hood there is definitely a master cylinder for brake fluid... That's why I really didn't think I had air brakes...although I do have air compressor and apparently 2 tanks. One with a pull cord on the driver's side and one with that auto bleeder as mentioned above.

For what it's worth here's an engine shot.

[sepudo]

Originally Posted by o1marc

When you start your bus for the first time, if the brake pressure is not built up you will not be able to release the parking brake. Bus will probably not start if it's not in neutral. When you start it thew compressors will start filling the tank until it has more than 60psi before the brakes will release. It will want to maintain around 110-120psi while running.Touching the brakes during this start up will make no difference.
Some will have a petcock to drain the tanks, some like mine have a pull cord that can be accessed from the side of the bus to pull that releases the water. Drain them daily.

You are right, when I start the bus the air compressors kick in and settle right above a hundred PSI...
Yet, as the new photos show, I do have a master cylinder with brake fluid... So if I "don't" have air brakes, what does the bus use the air for?

I wonder if there are Thomas bus owners manuals available somewhere. I searched online and didn't come up with anything.

[mmoore6856]

Originally Posted by sepudo

You are right, when I start the bus the air compressors kick in and settle right above a hundred PSI...
Yet, as the new photos show, I do have a master cylinder with brake fluid... So if I "don't" have air brakes, what does the bus use the air for?

I wonder if there are Thomas bus owners manuals available somewhere. I searched online and didn't come up with anything.

you stated you have air ride, correct?? thats what you need air for.

[Brad_SwiftFur]

I suspected as much. I'm betting you have a driveshaft parking brake operated by a lever as well. The air system will operate much like any other even if you don't have air brakes - likely for air-ride suspension (if equipped), air door (if equipped), air seat (likely equipped) and any other air accessories. With hydraulic brakes, I'd be surprised if you have air parking brakes (at least on the wheels themselves).


Many new trucks and road trailers these days have automatic systems that use the air supply to maintain the tires as well (I have no idea how easily or inexpensively this can be retrofitted). However, a quick-disconnect, an air hose and tire chuck are easily had and the next best thing for keeping tires up to pressure.

[mmoore6856]

the red, white and blue item on the primary tank is a automatic water spitter valve. every time the Governor signals the unloader valve in the compressor to shut off (when the tank reaches 120 psi)it will spit out any moisture it has collected

[mmoore6856]

i like the shut off valve by the primary (white) filter use it so you dont lose your prime

[sepudo]

Originally Posted by mmoore6856

you stated you have air ride, correct?? thats what you need air for.

No air ride. No visual airbags on my bus.

I do have air seat, air controlled door and from what I understand air parking brake. It's a yellow tab on the dash above the gear selector that I pull to activate and push to release.

[o1marc]

Originally Posted by sepudo

No air ride. No visual airbags on my bus.

I do have air seat, air controlled door and from what I understand air parking brake. It's a yellow tab on the dash above the gear selector that I pull to activate and push to release.

https://www.easternmarine.com/tech-i...ir-brakes-work

[EastCoastCB]

Originally Posted by sepudo

Under the hood there is definitely a master cylinder for brake fluid... That's why I really didn't think I had air brakes...although I do have air compressor and apparently 2 tanks. One with a pull cord on the driver's side and one with that auto bleeder as mentioned above.

For what it's worth here's an engine shot. Attachment 40362Attachment 40363

Looks nice and clean under the hood. I like that!

I'm real happy with my 3126. I've got the same bus as you but mines a 5 window.

[EastCoastCB]

Originally Posted by sepudo

You are right, when I start the bus the air compressors kick in and settle right above a hundred PSI...
Yet, as the new photos show, I do have a master cylinder with brake fluid... So if I "don't" have air brakes, what does the bus use the air for?

I wonder if there are Thomas bus owners manuals available somewhere. I searched online and didn't come up with anything.

IS your parking brake air operated?
My old shorty had hydro brakes but an air parking/e-brake. Is your door air operated?

[banman]

Originally Posted by sepudo

Under the hood there is definitely a master cylinder for brake fluid... That's why I really didn't think I had air brakes...although I do have air compressor and apparently 2 tanks. One with a pull cord on the driver's side and one with that auto bleeder as mentioned above.

For what it's worth here's an engine shot. Attachment 40362

Damn, your engine is clean...

Okay, going diagonally from lower left to upper right: 1) black can is your power steering reservoir 2) black hose running vertically between the silver and yellow cans goes to your eng driver air compressor 3) silver can is part of the HEUI pump 4) yellow can with 'CAT' on it is your primary fuel filter 5) is your hyd. brake resevoir. Directly below the hyd. res. is your ABS pump.

From your previous pix:
The brake on your tranny output shaft/drive shaft is cable actuated from the lever to the left of your steering column.
edit: just saw your post about air-actuated door & parking brake. Interesting... That would mean you need to build air pressure before driving -- the systems not just for funzzies like I'd want it...

The two wet hoses are for your tranny cooler. Check your fluid level. wipe down the hoses, check the connections for tightness (don't over tighten) wash the hoses off if possible and dry them again. Monitor them for continued wetness.

I'm excited to see your bus came with hydraulic brakes and an eng driven air compressor.
Means I can easily add onboard air to my build from a junkyard run...