Working underneath a trailer--best way to do it?

If all you're wanting to do is inspect and use a repair shop IF you see something wrong, I would suggest a mirror like the drug checkers use at the border. I use small mechanic's mirrors at work with a 2' collapsible handle to see things that are hard to get to. You could likely sit on a rolling mechanic's seat and see everything you could see climbing under.

If it's really a concern for you, just pick one out that's already high enough. Or get an "axle flip" done after the fact (if your new unit came with leaf springs). The only advantage that I can think of to the lower trailers is the amount of effort required to get in and out of them. Some people say they get better towing mileage and some people say they tow more stable. I don't buy into either of those arguments, and prefer good ground clearance.

myredracer wrote:
Only use jack stands or hydraulic jacks that have an ANSI/ASME label on them and have an appropriate wt. rating. Use a suitable plank under them. Do NOT use jacks or jack stands under the frame only for support.

Cribbing is the safest method for support if lifting the frame off the ground. From a structural point of view, to get max. stability you'd make the width of the cribbing twice the height of it. A lesser width at the base may work but ensure it's on stable ground - may need some planks to spread the load out. I would not do it like in the photo on a travel trailer as this could shift due to the tall height vs width of base. Don't support the frame at the 4 corners -support it fore and aft of the axles and put down the stab and tongue jacks. Make sure the trailer can't move side to side at the front or rear.

Another method is ramps like in the illustration below. Use X-chocks or equiv. and put down the jacks. This would be the fastest (and probably safer) method but the trailer will be at an angle (if parked on level ground) but could probably use ramps under the rear of the TV's tires.

Post a few pics of the work in progress. :)

No work in progress, no trailer yet. Just satisfying my curiosity.

Only use jack stands or hydraulic jacks that have an ANSI/ASME label on them and have an appropriate wt. rating. Use a suitable plank under them. Do NOT use jacks or jack stands under the frame only for support.

Cribbing is the safest method for support if lifting the frame off the ground. From a structural point of view, to get max. stability you'd make the width of the cribbing twice the height of it. A lesser width at the base may work but ensure it's on stable ground - may need some planks to spread the load out. I would not do it like in the photo on a travel trailer as this could shift due to the tall height vs width of base. Don't support the frame at the 4 corners -support it fore and aft of the axles and put down the stab and tongue jacks. Make sure the trailer can't move side to side at the front or rear.

Another method is ramps like in the illustration below. Use X-chocks or equiv. and put down the jacks. This would be the fastest (and probably safer) method but the trailer will be at an angle (if parked on level ground) but could probably use ramps under the rear of the TV's tires.

Post a few pics of the work in progress. :)

deltabravo wrote:

coolmom42 wrote:
Or is it better to raise the tongue jack and use bottle jacks under the axle?

NO.

Use Jackstands, which are a solid support.

Or park it on leveling blocks.

Or don't worry about planning how you are going to work on the underneath, and just go buy it.

That's pretty stupid advice.

I'm not WORRYING about it. But I do want to make sure this is something I can physically deal with, before I spend a lot of money. I don't want to be like someone in another thread on here, who has had a trailer less than a year and is about to eat the depreciation to trade it off, because he finds it too hard to deal with.

When I work under my truck, depending on the job, I just pull one side onto the curb. Would work with a trailer too.

As already said above..
I use HD Jack stands if I need the trailer elevated, not the cheap light duty ones. Wheel bearings and brakes will be about all that needs servicing regularly. There really isn't much need to be under the trailer for anything else.

JnJnKatiebug wrote:
I prefer the grass. Spread out a cheap big blue tarp and back the trailer over it. Much easier on my old bones than concrete. Easy to slide around on the tarp and things don't get lost in the grass.

That may work well for a cursory inspection when not elevating a trailer. It is not a good solution when doing bigger projects or when you need to elevate the trailer. Even if you support jacks and stands with wood pads, there is a good probability that those will sink into the ground or tend to tip. The tarp and lawn will be easier on your bones but bones snap and crush when 5000 Lbs comes down on them.
Please, folks, work safe or hire someone familiar with the process, if necessary. It only takes an instant to change your life completely.

coolmom42 wrote:
Or is it better to raise the tongue jack and use bottle jacks under the axle?

NO.

Use Jackstands, which are a solid support.

Or park it on leveling blocks.

Or don't worry about planning how you are going to work on the underneath, and just go buy it.

I raise my trailer using a combination of bottle jack and garage roller jack, as needed. Once up high enough, I use jack stands. After all that, I grab a few chunks of 6x6 or 6x8 wood (pieces of "landscaping" or railroad ties) and put them under frame points. This is basic "cribbing". I may use the wood just as an emergency stop - quick job - or I may lower the trailer onto them - long job. The nice thing about the wood chunks is that they are big and square, so plenty of room for the trailer to sit on them and they won't move like a bottle jack will.

The last time I did all that was to get 4 new tires. I lifted and secured the trailer, took off the wheels, and brought them to the garage for new rubber. I saved a small amount (mounting charge), but more importantly I know that the garage did not overtighten the lugs nuts with their air wrenches (which seems to almost always happen to me). Most of the rest of the important stuff under my trailer can be reached from the sides.