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Foretravel Motorhome Forums => Foretravel Discussions => Topic started by: Old phart phred on April 16, 2018, 10:31:26 pm

Title: Mechanics pit
Post by: Old phart phred on April 16, 2018, 10:31:26 pm
So I've got 49" between the duals plus a 6" safety zone on side leaves 37" wide maximun width. Going to have to hand dig this pit 34" deep by 15 ft length so I can have a hinged cover that swings down to safely cover it when not in use. I am thinking of a 32" wide pit would allow good access to most of the bottom of the coach. Any input would be valuable. I plan on using a roller stool to set on in the pit. Pit will be ventilated at pit floor level to vent dangerous heavier than air fumes.
Title: Re: Mechanics pit
Post by: Super8mm on April 16, 2018, 10:51:24 pm
I think I would just go rent a small backhoe for a couple of hours, could be much easier on a old back.

Come see me Sat or Sun  ;)
Title: Re: Mechanics pit
Post by: Old phart phred on April 17, 2018, 12:02:27 am
Running a backhoe inside a building is a skill set probably greater flying a jet to avoid collateral damage. A skill set few including me don't have. Shovel isn't, hoe rental is expensive by the time it takes to load, unload and transport, takes a day X 2.
Title: Re: Mechanics pit
Post by: Super8mm on April 17, 2018, 12:15:08 am
well there are these, I dont think you could hit a wall or ceiling if you had it in the center  :D

Mini (https://www.sunbeltrentals.com/equipment/detail/1253/0350110/2000lb-mini-excavator/)
Title: Re: Mechanics pit
Post by: joeszeidel on April 17, 2018, 07:28:12 am
Hire a couple of young bucks. You can supervise with a cold one.
Title: Re: Mechanics pit
Post by: nitehawk on April 17, 2018, 07:39:31 am
Back in my younger days, when I had a strong back and a weak mind, I helped a friend put in a pit in his garage. The soil was hard compacted red clay. He used his rototiller to break up a layer, we shoveled that out, then repeated the process until we got the depth he wanted.
Don't know the soil composition you have, but red clay is nasty when wet, and almost rock hard when dry.
Title: Re: Mechanics pit
Post by: Travelin' Man (RIP) on April 17, 2018, 07:51:09 am

Dig deep my friend.

https://www.youtube.com/watch?v=9FuY1zg7eIo
Title: Re: Mechanics pit
Post by: Travelin' Man (RIP) on April 17, 2018, 09:46:09 am
9 HP Towable Backhoe (https://www.harborfreight.com/9-hp-towable-backhoe-62365.html)
Title: Re: Mechanics pit
Post by: craneman on April 17, 2018, 09:58:33 am
I rented a small one from H.D. to run a sewer line 150' for a dump station for the '81 Don't remember the price, but save time.
Title: Re: Mechanics pit
Post by: Old phart phred on April 17, 2018, 10:22:01 am
Hire a couple of young bucks. You can supervise with a cold one.
They can't operate a shovel while holding their smart phone :o
I can multitask with a cold one with the proper headgear.
Dirt is loose Sandy and need the exercise.
How wide?
Title: Re: Mechanics pit
Post by: John44 on April 17, 2018, 10:28:54 am
Better figure out a way to line it if it's loose and sandy,we still have some young bucks here that will work and their not exchange
students.(did'nt get the headgear part).
Title: Re: Mechanics pit
Post by: Old phart phred on April 17, 2018, 11:01:28 am
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Title: Re: Mechanics pit
Post by: Pierce & Gaylie Stewart on April 17, 2018, 12:27:58 pm
So I've got 49" between the duals plus a 6" safety zone on side leaves 37" wide maximun width. Going to have to hand dig this pit 34" deep by 15 ft length so I can have a hinged cover that swings down to safely cover it when not in use. I am thinking of a 32" wide pit would allow good access to most of the bottom of the coach. Any input would be valuable. I plan on using a roller stool to set on in the pit. Pit will be ventilated at pit floor level to vent dangerous heavier than air fumes.

I will send photos of our pit when we get home. It's 35 feet long but I'm not sure of the width. It's deep with angle iron into the concrete so a roller support can be used to remove trans, etc. We are in Egypt and Istanbul for three weeks but will post how I did it when we get back.

Pierce
Title: Re: Mechanics pit
Post by: Keith and Joyce on April 17, 2018, 05:18:09 pm
Check to see if you will need any shoring to stop trench collapse.  At this depth you won't bury yourself but it can make the job harder it the sides go.

Keith
Title: Re: Mechanics pit
Post by: Old phart phred on April 17, 2018, 05:32:00 pm
pit is only 30 inches deep (not a full standing pit), shoring is required at depths greater than 60", I have hydraulic speed shoring available to use if need be.  Pits deeper than 30" require removable guard rails.
Title: Re: Mechanics pit
Post by: John Haygarth on April 17, 2018, 08:50:14 pm
I put one in and it is5ft deep and 36" wide. Used a back hoe and we are solid sand so did need the plywood sheets to hold sand back. I poured the base first then built up walls with concrete blocks with Rebar in drilled into 8" base then poured concrete into blocks and lots of rebar that was tied into more for the slab. That is also 8" thick. I have removable panels for a cover sitting on 2x8s which are set in recesses in walls every 24" to hold the 3/4" ply top. Simple to remove when coach is over it. I use a step ladder to get into it then move the remaining covers out of the way. This has worked very well for about 5 yrs or so. Time flies.
I did a posting on it with pictures so look at my old posts.
JohnH
Title: Re: Mechanics pit
Post by: Old phart phred on April 17, 2018, 11:00:02 pm
Thanks John I think I will go 36 in wide on the pit. If I cant back into that space without hanging a dual tire totally over it I need to learn how to drive. 30 in deep pit on a creeper puts my arms right above the floor level. Hopefully this is just for normal maintenance and access. If I go wider I may not be able to get a bottle jack underneath the rear axle while over the pit. Guess I need to check my frame rails spacing on my ORED. I have until next Wednesday to decide how wide to make it.
Title: Re: Mechanics pit
Post by: craneman on April 17, 2018, 11:23:52 pm
Phred, Can't think of anything you would need to jack it up for while in the pit. Brakes, axle bearings etc. you would be doing from the outside.
Title: Re: Mechanics pit
Post by: Old phart phred on April 18, 2018, 01:28:43 am
Keep it up guys, any input welcome. Coulda, woulda, shoulda is what I'm looking for as I am leaping into unknown territory at this point and wisdom is king. Been there done that speaks volumes about the pit itself.
Title: Re: Mechanics pit
Post by: fkjohns6083 on April 18, 2018, 10:31:10 am
Don't know what your water situation is, but you may need a well with a submersible pump in it.  I was able to get my pit in so that any water coming in would just run back out again. (day light basement style)  I made mine 10 ft long, 3 ft wide and 7ft deep and is just right for getting around.  I use several benches and short ladders to get to what ever I need to.  Changing oil was never so easy, not to mention changing filters.  I used 2 x 6s to cover my pit and are easily pushed up and moved out of the way from underneath.  If there is any way possible, You should consider concrete walls and floor.  Depending on the weight of your coach,  the width of the pit and soil composition, there will be a lot of weight in close proximity to the edge of the pit and could cause you some sloughing and sinking.  I would recommend having some one go over your plans with you and give you an outsider's opinion on things.  Take care and have a great day  ----  Fritz
Title: Re: Mechanics pit
Post by: Olde English on April 18, 2018, 08:34:06 pm
Don't forget the railroad ties, you can't bust through them. Just need to cast in a chase down each side.
Mick.
Title: Re: Mechanics pit
Post by: Old phart phred on April 18, 2018, 10:16:56 pm
I had planned on 8"concrete walls and 4"floor in the pit, with rebar to tie the upper and lower slabs together. Slabs will have WWF in them. No groundwater issues. Builder won't touch a mechanics pit even with a ten foot pole, so it will have to be done after inspection. BTW I have an BS-ARE engineering degree that included structural design for buildings, so soils theory, foundation design, structural analysis and building structural design with wood, steel and concrete. Along with building systems MEP,  I just chose the plumbing and HVAC side as a proffesion. 172 credit hours minimum just to graduate with a BS.