Floor pan

[Rick01]

I had my truck in the Mack shop for some repairs and wanted them to replace my brake foot valve.  Was quoted 2600 for a floor pan.   I couldn’t afford it on top of the 5000 repair bill.  
 Has anyone ever replaced a drivers side floor pan ?  I am going to try and do this myself but don’t want to make a mistake that will have me shut down.  
please advise me on this project . Do the pans just bolt in or does it require welding.  Two bolts holding the foot valve are broke and the pedal is loose

 thank you 

Edited October 30, 2021 by Rick01

[carlotpilot]

why would floor pan replacement come into play where repairing a foot valve is the issue?

[h67st]

6 hours ago, carlotpilot said:

why would floor pan replacement come into play where repairing a foot valve is the issue?

The foot valve is bolted into the pan, if the pan is rusted out there's nothing to hold the valve. Rick, I don't know your particular truck but pans are usually welded in.

[terry]

most floor pans are bolted in, some even around foot valve, depends what model he is talking about.   terry

[Rick01]

Thank you guys for responding. The truck is a 2002 RD688S.  The pan is not rusted thru but they mechanic at the dealership said the pan is bad.  

[Rick01]

20 minutes ago, terry said:

most floor pans are bolted in, some even around foot valve, depends what model he is talking about.   terry

2002 rd model.  

[Rick01]

1 hour ago, h67st said:

The foot valve is bolted into the pan, if the pan is rusted out there's nothing to hold the valve. Rick, I don't know your particular truck but pans are usually welded in.

The pan has some rust.  I will hopefully be able to repair this.   The truck is excellent. Only 120 k original miles.   Is it possible to Mount the new foot valve to the pan before bolting the pan down.   There isn’t much room to connect all the air lines 

[Rick01]

7 hours ago, carlotpilot said:

why would floor pan replacement come into play where repairing a foot valve is the issue?

They said the pan is bad.  It looks to me like the aluminum foot valve is broken around two of the bolts . I can’t tell exactly tho without taking it apart.  

[Joey Mack]

You can remove the small pan that contains the foot valve. 13mm socket to remove the ring of bolts and the seats.  when you get the brake pedal off the base, you can cut the foot valve bolts off. the pedal base is likely junk at this point. when the valve is detached, you can pull the pan ..  then buy all the speed nuts for the ring of bolts as needed, and the 2 speed nuts and screw's for the heel plate.  leave the valve connected and mark the lines 'well' so when you swap valves, you don't end up scratching youre head.  these pans are farely thick, and with a Mini MIG welder, you can repair them.  of course there arent any pics of the damage. before I forget, pull both seats out, it's a heck of a lot easier to move around in that tight cab.  Keep in touch, Jojo

[MACKS]

You would be surprised how much the floor pan will flex when stepping on the brake pedal if it weak and rotted, your gonna feel the difference after u fix it..

[Vladislav]

The way of things is quite simple there. The floor conteins 2 removable parts. A larger one is at the right and a smaller at the left. The treadle valve is installed in the left one. Both panels attached to the main cab floor by a raw of screws. You probably would be good having only left (small) part removed. But may be wanting to take care of the larger one too if they both are rotted indeed. Both parts have simple shape and can be repaired by weld if the new parts cost is not friendly. So follow the advice Joey Mack gave to you. The valve has 9 or 10 or so air lines attached so there's a need to mark them. The seat remove would be of help no doubt but maybe it would be enough to get rid of only the driver's one.

Edited October 30, 2021 by Vladislav

[Rick01]

6 hours ago, Joey Mack said:

You can remove the small pan that contains the foot valve. 13mm socket to remove the ring of bolts and the seats.  when you get the brake pedal off the base, you can cut the foot valve bolts off. the pedal base is likely junk at this point. when the valve is detached, you can pull the pan ..  then buy all the speed nuts for the ring of bolts as needed, and the 2 speed nuts and screw's for the heel plate.  leave the valve connected and mark the lines 'well' so when you swap valves, you don't end up scratching youre head.  these pans are farely thick, and with a Mini MIG welder, you can repair them.  of course there arent any pics of the damage. before I forget, pull both seats out, it's a heck of a lot easier to move around in that tight cab.  Keep in touch, Jojo

Thank you for the information. I was hoping maybe if I can remove the floor pan with foot valve on it I might have room to move one air line at a time . 

[Rick01]

8 hours ago, h67st said:

The foot valve is bolted into the pan, if the pan is rusted out there's nothing to hold the valve. Rick, I don't know your particular truck but pans are usually welded in.

Thank you for replying.  I will remove the floor mat and then hopefully I will be able to tell more about it.  I have a new foot valve and pedal but not floor pan.   I hope it’s something I can fix.   If I had the money I would have had the dealership fix it.   I just got my truck back from them with a 5000 dollar invoice for a new manifold and all new epu bolts.   

[Rick01]

4 hours ago, Vladislav said:

The way of things is quite simple there. The floor contein 2 removable parts. A larger one is at the right and a smaller at the left. The treadle valve is installed in the left one. Both panels attached to the main cab floor by a raw of screws. You probably would be good having only left (small) part removed. But may be wanting to take care of the larger one too if they both are rotted indeed. Both parts have simple shape and can be repaired by weld if the new parts cost is not friendly. So follow the advice Joey Mack gave to you. The valve has 9 or 10 or so air lines attached so there's a need to mark them. The seat remove would be of help no doubt but maybe it would be enough to get rid of only the driver's one.

I sure hope I have that small pan under foot valve.   Is it possible to remove the little pan and the pedal and valve will allow enough room to replace all the air lines or is that wishful thinking 

[Vladislav]

7 minutes ago, Rick01 said:

I sure hope I have that small pan under foot valve.   Is it possible to remove the little pan and the pedal and valve will allow enough room to replace all the air lines or is that wishful thinking 

Yes, that's about that. My target was transmission swap so we removed both floors. But as I remember we did that partially. Took the screws off and than lifted the big floor a bit to access to the air lines. As long as I remember we didn't remove the treadle valve off the small floor when in the truck just took them off together. You need to pass the gear shift lever through the hole to get the big floor off (completely) and need space to do it and better two men to not scratch the dash etc. We did that 3 years ago and now I don't remember all the nuances. The screws were rusty and the floors either and if the memory serves well we took one floor up a bit and than the other and achieved the air lines. Something like that. All in all I remember it was relatively tight in the cab indeed and multiple air lines quite similar by the look but nothing extraordinar of a job to do. Some of the air lines can (and should?) be accessed from under the hood. The valve is visible if you look under the cab floor at the driver side from the engine compartment.

[Joey Mack]

Just a side note here... my thought's.  One thing I love about this web site, is that people from around the world can get together and help 'one-another' .. What a great forum!   You go B.M.T. .....  Jojo..

[Rick01]

15 hours ago, Vladislav said:

Yes, that's about that. My target was transmission swap so we removed both floors. But as I remember we did that partially. Took the screws off and than lifted the big floor a bit to access to the air lines. As long as I remember we didn't remove the treadle valve off the small floor when in the truck just took them off together. You need to pass the gear shift lever through the hole to get the big floor off (completely) and need space to do it and better two men to not scratch the dash etc. We did that 3 years ago and now I don't remember all the nuances. The screws were rusty and the floors either and if the memory serves well we took one floor up a bit and than the other and achieved the air lines. Something like that. All in all I remember it was relatively tight in the cab indeed and multiple air lines quite similar by the look but nothing extraordinar of a job to do. Some of the air lines can (and should?) be accessed from under the hood. The valve is visible if you look under the cab floor at the driver side from the engine compartment.

Yes sir.  I have looked at the valve under the hood and it looks near impossible to change some of the air lines unless the floor pan is removed .  

[mrsmackpaul]

My 20 cents worth if I  may

If you dont have a pocket full of coin then just cut out the rust and weld bits snd pieces in here and there 

Try to do only a patch or two and make the patches a lot bigger the hole your trying to cover

Do not over lap stuff to weld it, it might be easier but it will only trap moisture and rust out quicker than before

Butt welding with 0.6 mm or 24 guage (according to Mr Google) take your time and you'll be surprised at just how good a job you can do with out spending bugger all 

Also if your gunna weld, folg the ton foil from the cooks kitchen draw and wrap your airlines as best as you can as these melt thru with splatter from the MIG, quick as look at you

Good luck and keep us posted 

Try a truck wreckers for cuts from a floor to make the patch for yours, gunna get a lot of bits for 2 1/2 grand

 

Paul

[Rick01]

33 minutes ago, mrsmackpaul said:

My 20 cents worth if I  may

If you dont have a pocket full of coin then just cut out the rust and weld bits snd pieces in here and there 

Try to do only a patch or two and make the patches a lot bigger the hole your trying to cover

Do not over lap stuff to weld it, it might be easier but it will only trap moisture and rust out quicker than before

Butt welding with 0.6 mm or 24 guage (according to Mr Google) take your time and you'll be surprised at just how good a job you can do with out spending bugger all 

Also if your gunna weld, folg the ton foil from the cooks kitchen draw and wrap your airlines as best as you can as these melt thru with splatter from the MIG, quick as look at you

Good luck and keep us posted 

Try a truck wreckers for cuts from a floor to make the patch for yours, gunna get a lot of bits for 2 1/2 grand

 

Paul

Thank you for replying.  I am going to try to repair today.  

[Rick01]

On 10/30/2021 at 7:27 AM, terry said:

most floor pans are bolted in, some even around foot valve, depends what model he is talking about.   terry

My truck is 2002 RD688S. I hope I have the small pan that foot valve bolts to.   

[Rick01]

23 hours ago, Joey Mack said:

You can remove the small pan that contains the foot valve. 13mm socket to remove the ring of bolts and the seats.  when you get the brake pedal off the base, you can cut the foot valve bolts off. the pedal base is likely junk at this point. when the valve is detached, you can pull the pan ..  then buy all the speed nuts for the ring of bolts as needed, and the 2 speed nuts and screw's for the heel plate.  leave the valve connected and mark the lines 'well' so when you swap valves, you don't end up scratching youre head.  these pans are farely thick, and with a Mini MIG welder, you can repair them.  of course there arent any pics of the damage. before I forget, pull both seats out, it's a heck of a lot easier to move around in that tight cab.  Keep in touch, Jojo

I hope I am able to get to all the airlines.  There is no room from under the hood.   I think it’s going to be very tight unless I can take the floor pan loose and get to the needle valve 

[mrsmackpaul]

Assuming its a air ride cab, you can stick a jack and piece if wood etc under the back of the cab and lift it right up to full travel and you may get another couple of inches to work in to access the air lines

 

Paul