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Randy J. 09-02-2015 04:17 PM

Tie down bolts and frame - old Trillium
This probably isn't new - except to me. While doing some sprucing up of the cargo holds on the old Trill I noticed one of the tie-down bolt heads and square metal "washer", nearest the freshwater tank drain, looked severely rusted. A little pry with my screwdriver and the head popped right off! This is the only one I've seen to be rusted but I'll apply some torque to the rest, just to be sure and replace this one and probably oversize the steel plate/washer. The floor around the area seems solid. I had already added an extension to the drain spigot.

Questions for Trillium owners:

Has anyone had similar experience?
Think I should just replace the rest of the tie-downs?
Are there any torque specs?
The floor seems solid, as does the frame. I nonetheless have the frame treated by Crown every few years. And it doesn't seem that these fail, at least on old Trilliums. Anyone heard anything different?


David Tilston 09-02-2015 06:01 PM

Randy, The bolts are a week point on Trilliums. You don't say if yours is a 1300, or 4500. On the 1300, there are six bolts. On a 4500, there are eight.

I would replace them all.

Randy J. 09-03-2015 06:21 AM

Tie down bolts
Good advice! Mine's a 1300 - six bolts. Curiously they put four in the back, two on each side but only two in the front.

Any idea of the specs? I'm thinking of using stainless, if I can find it, and of course lock washers. And probably a hex head rather than the carriage bolt. Carriage is lower profile but the steel plate was just round-drilled - no idea how they got the bolt to hold still while they torqued the nut. This way I can just drill the new plate.


Larry C Hanson 09-03-2015 08:20 AM


Ran into a similar problem when I bought
my '78 Trill...

Take Care,
Larry H

David Tilston 09-03-2015 08:34 AM


Originally Posted by Randy J. (Post 546068)
Good advice! Mine's a 1300 - six bolts. Curiously they put four in the back, two on each side but only two in the front.

Any idea of the specs? I'm thinking of using stainless, if I can find it, and of course lock washers. And probably a hex head rather than the carriage bolt. Carriage is lower profile but the steel plate was just round-drilled - no idea how they got the bolt to hold still while they torqued the nut. This way I can just drill the new plate.


When I had my trailer fixed up, I had them put the bolts in upside down. That way the nuts and threads are inside the trailer. The porta-potty still fits over the nuts in the porta-potty garage, under the gaucho.

Torquing the nuts is easy, if you use an impact wrench.

floyd 09-03-2015 09:45 AM

My Trillium 1300 had corroded bolts so bad that you could lift the body off the frame at the corners. Not one bolt survived removal.I used stainless bolts, nuts and washers for replacements with great confidence. You really don't need a torque wrench, just compress the lock washer until it is flat. You can use threadlocker if you have it or you could spray the exposed threads with undercoat or paint as a touch of added security.

getaway1 09-03-2015 01:23 PM

To prevent rusting of any bolt & nut use a setting seal wax ring for toilets and smear it on. It is bee's wax. You will be glad you did when it's time to remove any bolts later on.

mary and bob 09-03-2015 01:57 PM

UHauls typically have rust issues with the body bolts. They are 1/4" elevator bolts and rust away where they pass through the floor so the problem can't be seen until they are removed

Randy J. 09-03-2015 02:14 PM

Tie down bolts
Well, thanks for all the advice. The tie-downs I discover require three things to keep the trailer secure - the bolt, the metal plate or washer, and a sound plywood floor in between. So another point of concern is how sound the the 40 year old plywood might be under that fiberglass. It seems solid but having replaced the rotten window frames I'm leery. I'll at least give it a screw test. And even so, I'm thinking of adding an extra thickness of plywood, then putting the bolts through everything.
If I wanted to have someone else do this, would the RV place be where to go or is there somewhere that deals specifically with trailers?


David Tilston 09-03-2015 03:23 PM

Randy, I am not sure what you mean about the plywood under the fibreglass. Where the bolts go through should be exposed wood, but with some resin painted on it.

Randy J. 09-03-2015 04:32 PM

Well yes, I suppose that it is just resin on the topside of the plywood - a very thick layer of resin which we hope has kept the wood dry and sound all these years.

Randy J. 09-03-2015 04:34 PM

Come to think of it though, the fact that it is just a coat of resin and seems sound probably tells me the wood it coats is okay. Right?

David Tilston 09-03-2015 04:58 PM

That would be my guess.

Thinh 09-03-2015 06:50 PM

Here are your trailer bolts, same like mine. Just cut them off, replace with new one. Even the new bolts are regular steel, you will have a peace of mind in the next...20 years..

Don ravinerat 09-05-2015 06:38 AM

I just had my Trillium off the frame. All my bolts were rusted and two were almost rusted through. Replaced them with stainless steel. Bolt, washer, lock washer and nut. Well worth it.
Now here is my problem. The tray that the porta potty sits on. How is it attached? my final bolt to replace sits under it and It can't get at it. Anyone removed this "shelf/tray" before?

Randy J. 09-07-2015 06:21 PM

I will use regular steel bolts, partly because I don't want to set up a possible galvanic situation with the frame and partly because, as Tom from Trillium Parts tactfully suggested, I don't need them to last another 40 years!

Why are you removing the body from the frame? Are you concerned about frame rust? So far as the floor goes, shouldn't the fiberglass shell be protecting the wood floor? In an ambitious moment I have thought about separating the frame and having it painted. But Krown Rust proofing seems to seep everywhere and I'm pretty sure it must have gotten between the tube frame and the body. Anyway, any pictures of how the heck you do it would be interesting!

Someone was asking how to remove toe porta-poti garage. I've long since removed ours because it stunk to high heaven - no bolts, just some screws - and have no plans to replace it. We carry Old Stinky (when we must!) in a sealable tote.


Don ravinerat 09-08-2015 05:59 AM

I replaced my bolts with SS on the recommendation of the trailer place. Anything I do to the trailer will last the length of time I own it for sure.

We removed the body from the frame so not to damage the Fiberglass when welding the new axle on. I got to have a good look at the frame and it is solid. I will be able to remove the body for painting of either the frame or the body when the time comes. I was thinking on using the bed liner stuff for the frame but I will look into that later.

I got the little shelf out and it was held in by 4 little screws. I've just got it sitting in there right now. I'll have to see if it bounces too much

pogophile 09-10-2015 02:44 PM

Bolt specs
2 Attachment(s)
First off, ours is a 1980 Trillium 1300. That means that the frame is different from many of the earlier years; there are gussets welded to the "upcurve" right under the forward edge of the body to prevent the cracking often seen in earlier frames. Also, and I'm not sure if this is just on the later models or not, the forward two body-to-frame carriage bolts are not through the frame like the four in the back, but rather through a heavy steel angle bracket welded to the side of the frame when it was built.

So bearing in mind that other versions of the trailer may be different, here are the specs of the bolts I removed:

4 at rear: 5/16" mild steel carriage bolts 5" long, 18tpi, with square-punched backer plate on top and split washer and 1/2" nut on bottom.

2 at front: 3/8" mild steel carriage bolts 2 1/2" long, 16tpi, with square-punched backer plate on top and split washer and 9/16" nut on bottom.

Of the six, 3 were very badly corroded and reduced to a fraction of their original diameter, in all cases near the head where the damage was not visible. Likely this is due to exposure to wet plywood in the floor sandwich brought on by leaky window seals (fixed).

In other parts of this thread one user noted that his backer plates were round-drilled. In my case all six were machine punched with a square hole that matches the carriage bolt sub-head. This makes nut tightening down below easy: no spin up above. Maybe the square holes are on the newer Trills?

One user mentions installing the bolts with the nuts and washers on the top. I chose not to do this. My concern? I have seen split washers snap in the past. It's not common, but it happens. When it does, there is a danger of having the nut come loose. (At least until it is rust-seized :loltu).

If this happens in the original configuration, the bolt will probably stay put. If things are upside down from the original, and the nut "walks" off from a failed washer and vibration, the carriage bolt or hex bolt will fall out on the road. Remember that the load on these bolts is almost always "in shear", meaning they act to stop the body from sliding on the frame. I figure a bolt in the hole is worth a hundred on the road.

I ended up replacing mine in exactly the same configuration the manufacturer used, and I used the same type of mild steel carriage bolts. I did use some high-end caulk under the backer plate and around the bolt shafts where they went through the floor. On the rest of the bolt, I applied a generous coating of bearing grease.

My plan is to remove the body and clean and paint the frame next year. When I do, I may reattach using stainless. If I don't get to it, well, I'm pretty sure these will last longer than I will.

As other users have said: if you haven't done this yet, there's still time before the snow flies. It took less than a day.

Don ravinerat 09-10-2015 03:45 PM

All 6 of mine are 5/16 x 5" with a square hole punched backer plate. Washer, loc washer and nut. 1974 Trillium.

Randy J. 09-10-2015 04:19 PM

Well, thank you all - for all of that! Tom of Trillium Parts (some of you may know him - the original Trillium guy!) suggested just using the same size steel bolts from Home Depot. I haven't pulled the other bolts yet but suspect some of you are right about the "square punched" square washers. The washer that broke off with the carriage bolt head is too corroded to see for sure and can't be re-used. Don't know where I would get a replacement square punched, unless I somehow do it so at least that one will have to be a hex head (maybe my wife will consent to hold the wrench on the top side:) I'll ask the hardware store to at match the specs of the bolts I buy to the ones I take out.

Glad to hear the fellow who removed the body found the frame in good shape - also reassuring for the rest of us.


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