mechanics pit

[happycamperbrat]

Over the period of the next few months I am hoping to put in a full length mechanics pit and garage floor with an enclosed area for storage on the north side. Eventually I want to add on to the enclosed strage area and put up a carport at least 16 feet tall, then wall in the other south side and leave enough overhang to park a car or use it as a breezeway. Then in the next step of construction I want to close up the east and west ends but put on doors so it would be a drivethru garage. I am figuring on the garage floor being 50-60ish feet long (E-W) and 35ish feet wide (N-S). This will all be done in phases as money and time allows. I am even looking into doing a bunch of this with stabalized earth (which is 15% cement and 85% dirt). My question is this: for the mechanics pit I want it the full 40 ft length of the bus (maybe a little longer to get in and out?) but I dont know how deep to make it. I am thinking it would get to be a hazard to pull in and out of the garage daily with a huge hole in the middle lol.  So maybe if I only made it a couple feet deep to run a creeper up and down it? This is all new to me and I am learning as I go, so to tell the truth I have never worked under a vehicle before and really want to hear what you all have to say about it. Thanks!

[Kenny]

I say if your going to do it from scratch, go with a 45' long by 5' deep pit with a drain. But please remember you should also provide proper forced fresh air ventillation into the pit. Prior to entering a pit like this the fresh air ventillation should be running.
Kenny

[happycamperbrat]

Thank you Kenny! How wide do you think it should be? And would some sort of bumpers or something else be advised to avoid driving off into the pit lol?

[luvrbus]

Depending on where you live and noticing you are going to use cement for stabilization it must be sandy soil it could be a mistake making a pit the same length as the bus I seen those long pits collapse before and most are 5 ft wide and 5 ft deep with the walls extending 4 to 6 inches above the floor for curbing.  
I would do one 20 ft long and cover with grating when not in use just my way you add 15.00 a sf for walls and floors the cost will be over 10 grand on a 40 ft pit to be safe. FWIW there is nothing to check on the bottom of a bus in the middle it is all on the front and rear,  sorry I have no idea why I told you 5 wide looking at some old Wal/Mart plans they are 4 ft wide from the outside walls


good luck

[Just Dallas]

Removed

[happycamperbrat]

Im totally interested in it being safe. 20 ft sounds reasonable if that is mostly all I will be doing is checking the front and back. I have future plans of installing a hitch but having the steel extend up to the front of the bus instead of just on the back engine cradle and there are a few other things I want to do which would require getting under the bus for the full length. But I guess if the pit were only 20' long that I would still be able to do those things by improvising?

And yes, I intend on having some sort of drainage and even electrical outlets down there for power tools.

[John316]

As Kenny said, make sure you have the ventilation that is a good ideas (by the NEC ).

Also you will want lights down there.

I wouldn't cut corners on the support. If it was me, I would do at least 8" walls, with rebar on one foot centers. Also, you could also have the fibers put in the mix too. You don't want to compromise your safety.

FWIW

God bless,

John

[happycamperbrat]

Actually I was thinking about the stabilized earth for walls for the garage/storage area and maybe the floor of the garage....... not necessarily for the walls for the pit. However, for the pit I was thinking about those concrete blocks at Home Depot and "maybe" filling them with stabilized dirt? For ventilation, would having protable fans down there do it? Or do I need something more sophisticated? lights is also a good idea!

[Kenny]

Personally I would use a minimum 4 bag concrete mix with rea bar for the walls with a minimum 8 inches thick. I have seen concrete basement walls cave in from very heavy vehicles driving adjacent to the wall.

Also, ventilation should be drawn directly from a fresh air source and routed to the bottom of the pit. Would use HVAC duct. Please keep in mind that even though a vehicle is not running, just the act of pulling into the pit area, exhaust fumes will find the bottom of the pit and stay there long after you've shut off the vehicle. This goes for most cleaning fluids you may be using else where in the garage area. They will also find the bottom of the pit and without proper ventilation can be very deadly to breath and explosive. Have seen this happen too many times.
Kenny     

[happycamperbrat]

Okay! Thanks! You may be saving a life  For the strength of the pit walls, how about using concrete 8" blocks and additionally making the floor 8" deep concrete with rebar around the pit for about a one foot distance?

[Len Silva]

I had a pit built at my previous shop.  It was 3-1/2' wide and 5' deep.  You don't want to go too wide so that you have a good solid surface for jacks along the sides.  Mine had a 3" x 1-1/2" lip all around so that it could be covered by 4" wide stock.  I used doubled up 3/4" plywood for a cover.

Mine was 24 feet long and worked OK.  Kind of a pain if you wanted to work on both ends of the bus.

I used 6 inches of reinforced concrete in the floor with a slight slope to one end.  The walls were cement block with rebar and concrete filled.  Remember that the floor and walls of the pit are what is holding up the floor of the shop with the weight of your bus on it.

I had a sump at one end plumbed out and both electric and compressed air piped in.  I had a blower to keep the air moving mostly because it can get hot and sticky down there in Florida.

I did not have curbs as I wanted a flat floor when the pit was not being used.  I used black and yellow safety tape on the floor just outside of the wheels and a large parabolic mirror on the back wall to help me drive in straight.

It always scared me driving in, afraid I would drop a wheel in the pit.  I used to watch mechanics in a bus shop come rolling into the garage and over the pit in one smooth motion, always impressed by their driving skills.
 
Theoretically, you should use explosion proof wiring but I did not do that.  If I was working on gasoline powered vehicles I might have paid more attention to that.

[happycamperbrat]

Is 5' deep safe to get under a bus without jacks? This is another issue I am struggling with......... is a pit safe? I mean all the time I am being warned about not getting under the bus because the air bags could go and I would be a pancake. So, since I am taller then 5' what happens when/if the bags deflate?

[sweeney153]

Duck

[luvrbus]

Do your knees bend seriously never pull the bus over the stairways always leave yourself a escape route or a entrance for someone to help if needed.
How far does a RTS drop without air most buses drop 6 to 8 inches.We all have a preference but I am not a huge fan of pits myself too much lost floor space very seldom in the past 20 years have I seen a new shop built with a pit.
Really about all they are good for is lube and oil change and minor repairs like on the air system



Good luck

[happycamperbrat]

well, this is another reason I was considering a crawl space rather then a deep pit to stand in. If it were only a couple feet deep and the bus deflated the sides of the pit and floor of the garage would support the weight and I could crawl out........