Mac classic trailer axle

[walt]

I finally started to do some projects on my trailer. The main thing I wanted to for sure do was to put in a new set of bearings and races, new grease. So far, I have removed one side and found the bearings apearing to be in great shape after nearly 10 years but Ill replace them anyhow.

Im a fan of this trailer.. it looks too simple (like the boat also) but both the boat and trailer now are 26 years old with dang little sign of wear. Ive personally put maybe 15K miles on that trailer.

I like the single axle (for a bunch of reasons - but this thread is not about single or double axle) and thought about replacing the axle as mine has a slight bend to it but apparently the Mac trailer axle is some custom size. The axles I found on etrailer were 89 inch hub face to hub face, 74 inch spring to spring or the lighter duty axles are 72 inch hub face to hub face. The axle that is on my 26S trailer is around 81 inch hub face to hub face and 68 inch spring to spring. If I could find a heavy duty "bolt in" axle, I might go that route but will just leave it as is if a hassle is involved.

One simple thing I was just thinking about... is to add about a four foot length of angle iron to the axle to stiffen it a little. Four foot length was chosen as I would not have to modify anything on the axle for this to fit. The stiffener would be held on with 4 to 6 Ubolts or something like that. No welding.. just bolt it on with some consideration for corrosion from trapped water.

Is this a bad idea.. dangerous.. etc.. That last picture is the hub after 26 years.. I may also replace the hub and go with disk brakes this year.. or maybe not.. after all, its worked fine for 26 years.

 

[justsomeguy]

apparently the Mac trailer axle is some custom size.

Interesting. One would think 'ol Roger would've spec'ed a readily available axle.

add about a four foot length of angle iron to the axle to stiffen it a little...Is this a bad idea.

I don't think so. You seem to have a head for figuring stuff out, and with the U bolts, no harm no foul iffen it don't work out.

 

[RussC]

I had planned on replacing the axle on my trailer a few months ago due to being way out of alignment, but I discovered the same problem with not being a "standard" configuration. I ended up re-aligning the old one myself, which was actually not that difficult, and then adding a truss to the bottom to stiffen it up. bolting on an angle iron brace may not be as simple as you imagine, because the axle will not be straight, if the wheels are properly aligned. you might be able to add shims between the angle iron and axle beam, but it's something you'll need to keep in mind. a truss setup adds MUCH more stiffness that the angle iron would however.

Custom alignment machine (your new boat shelter support post would work great also):

truss system (fabricated from 1" square tube and welded to axle):

 

[Barnacle Bill]

Believe it or not, sometimes trailer manufactures put a little bend in an axle on boat trailers. But, if yours was once straight and now it isn't, then the above fact is probably not the case. Replacing an axle isn't a big job, actually and you'd be surprised at how inexpensive they are. Wheels are separate and so you'd have to remove them and retrofit them to the new axle.

 

[walt]

The no load bend in my axle goes the "wrong way" so I think its just due to loading over many years. I think also Macreggor was a high volume manufacture in 1990 (the year of my trailer) and with high volume, you can specify whatever you want, buy a lot of them and get a good price.

Russ, I was actually thinking about what you had done to straighten the axle (I like that method) and you are right, those big I beams holding up the shade would do the job (good thing since the only thing that resembles a tree around here are cactus.. might not work so well).

Im hesitant to do any welding on my axle as I dont think my welding skills are up for that. In the picture below, you can see my all bolted together Aluminum goal post. The original steel one had busted and I "fixed" it myself with a MIG welder.. Well.. it broke completely off the trailer driving in Long Beach CA this last summer. Fortunately it was tied to the trailer light wire so I just dragged it.

 

[walt]

update..

Ive been using Etrailer for info which might be a little limiting..

Here is a 3500 pound axle just for reference https://www.etrailer.com/Trailer-Axles/Dexter/T3584F-EZ-8974.html The diameter of the "tube" is 2 3/8 inch. If you look at their 2200 pound axles, the tube diameter is 1 3/4 inch.

The axle on my 1990 26S axle is rounded square shaped with a diameter of 2 inch. So exactly what the rating of this axle is.. I dont know but it would seem to be somewhere between 2200 and 3500..

I have now taken apart both hubs and the bearings on both sides are in good shape after all these years. However.. I think I still going to replace them now with disk brakes. This is what Im just thinking about - have not ordered anything yet.

First, I think this is the disk brake hub set I "think" would work - pretty much just unbolt the old drum brake and bolt on this https://www.etrailer.com/Trailer-Brakes/Kodiak/K2HR35D.html ($259)

This brake set says it is for a 3500 pound axle so I checked the bearings that are specified for it (L46149 and L44649). The spec for the ID on those bearings (from Etrailer) is 1.378 for the inner bearing and 1.063 for the outer bearing..

I measured my axle and I get 1.07 and 1.375. The caliper I have is lacking a little in resolution so I "think" this would all be a good match. And it interesting that the bearing size on the stock 26S axle is the same as the 3500 pound axle..

I would also need to replace my surge actuator as these are different for disk or drum brakes.

 

[walt]

Looking at the surge actuators for disk brakes.. the options are here https://www.etrailer.com/dept-pg-Brake_Actuator.aspx

The one I think I would order is this one
https://www.etrailer.com/Brake-Actuator/Titan/T4715400.html

Its similar to what I have now which is set up for drum brakes so Im fairly sure it would be an easy swap. You can get these with an electronic solenoid that locks out the surge coupler for backing the trailer up but it would require a wiring mod that I dont want to deal with. Plus.. reading some reviews, when problems occurred, there are a few accounts of it being that electric solenoid. Trailer brake systems are hassle enough. I understand the reverse lockout is more important with disk brakes compared to drum brakes but Im not sure about this. The one I picked says it has "no reverse lockout" but if you scroll through the pictures, you can see a pin that you manually insert for the reverse lockout.. The manual pin is what I want.

 

[centerline]

truss system (fabricated from 1" square tube and welded to axle):
View attachment 131145

this is a great job of trussing an axle.... but its overkill for the weight of a 25-26ft macgregor sailboat loaded for cruising.. that method can more than double the strength of the axle tube between the springs.

a quality axle over 60" wide should have some over bend in it to allow for the crown of the streets and secondary roads, but not all axles do which is ok for light loads, but with a moderate or heavy load a bit of camber in the axle is preferred.
6-7 ft axle laying flat on the floor could have anywhere from 1/2" to 1" of overbend in it, in an attempt to decrease tire wear.

rather than the angle iron, I would find someone to weld a single piece of 2" wide x 1/4" or 5/16" thick flat bar to the bottom of the axle.... (skip welded 2 inches every 3 inches or so) this would truss it plenty strong (about 28% stronger than original) but may take some trimming if the axle has camber in it already. if it has negative camber due to being overloaded in the past, the axle will be able pulled back to the flatbar a little and the welding at the bottom of the tube will help "shrink" it into place.... its simple, quick and a proper fix for the problem within the weight range that the tires or spindle end of the axle could ever withstand, safely and dependably.....

 

[RussC]

this is a great job of trussing an axle.... but its overkill for the weight of a 25-26ft macgregor sailboat loaded for cruising.. that method can more than double the strength of the axle tube between the springs.

I've always felt that any project worth doing... is worth overdoing.
My axle on the 25 is a drop configuration, and already had the drop stub protruding below the main axle tube, so it was well suited to welding the 1" tube truss to it in the way I did. it looks like Walts axle may be straight however, with no drop at all, so it may better lend itself to other methods.

a quality axle over 60" wide should have some over bend in it to allow for the crown of the streets and secondary roads, but not all axles do which is ok for light loads, but with a moderate or heavy load a bit of camber in the axle is preferred.
6-7 ft axle laying flat on the floor could have anywhere from 1/2" to 1" of overbend in it, in an attempt to decrease tire wear.

I know you know this, but just to be clear: weather or not the axle tube has a bend isn't important. what is important is that the wheels/tires have suitable camber and toe in for the application. it seems like most manufactures build their axles/spindles straight, and then bend the tube to get the correct camber and toe. not sure why they do it that way, but that seems to be the case. No need to overthink the alignment method, and I've found that simply taping a stick to the sidewall of each tire, overhanging the tread by a couple inches on each side, provides a very satisfactory method of taking the camber and toe measurements.

.02

 

[centerline]

I've always felt that any project worth doing... is worth overdoing.

weather or not the axle tube has a bend isn't important.
what is important is that the wheels/tires have suitable camber and toe in for the application.

it seems like most manufactures build their axles/spindles straight, and then bend the tube to get the correct camber and toe.
not sure why they do it that way, but that seems to be the case.

They do it that way because its cheaper and easier to have a straight spindle jig then insert any length of tube in and weld it up then bend the tube to the desired camber..
When they weld the spindles to the tube it takes about 10 seconds per spindle, and with a quick weld there is very little warpage or pulling the spindles out of position, and after welding on the spring seats, quick bend of the axle will evenly camber it...

With the axle being bent, even without spring seats on it, its easy to tell which is the top of the axle tube, whereas with the spindle being welded with a camber on to a straight tube, its quite a bit harder to tell if everything is even... but it can be done by a careful person, but takes much longer.

 

[walt]

FYI, both the 2200 and 3500 axles from etrailer say this

• Bend in axle creates zero camber angle for even road-to-tread contact across the width of your trailer's tires

The toe in on my axle changes with load going from looking like it has the bend of a small load when there is actually no load to too much camber under the boat load. But my axle may have had the correct "pre bend" when that trailer was new many years ago, dont know. Ie, its maybe somewhat of a spring that is a little worn out. It does wear my tires on the outside edges but I still get over 5 years on the tires so they "expire" before wearing out. If an axle has prebend that flattens out under load (which maybe is more of the norm than exception), that also means the axle is at least a small part of the suspension. I think it also says that the zero camber angle best occurs for some specific loading. Ie, you would want to use the 3500 pound axle on a trailer that has about a total load of 3500 pounds for best tire wear. There is some speculation in that on my part in the above..

I thought the 26S trailer was about as good as you could get for keeping the boat low to the ground but that drop down part in Russ picture would get the trailer maybe two inches lower. For a somewhat typical 10% slope ramp, that would mean you would need to back the trailer in 20 inches less than with a straight axle. Ive got 15 inch tires so slightly raised my trailer over stock (14 inch) but that boat is still easy to load.

 

[Sumner]

....I thought the 26S trailer was about as good as you could get for keeping the boat low to the ground but that drop down part in Russ picture would get the trailer maybe two inches lower.....

Looks like someone negated most of the effect of the dropped axle with the addition of square tube spacers between it and the springs.

If I was going to try and reinforce the stock axle it would be good to follow the example above since it improves the strength of the entire length of the axle. To reinforce it with something that stops short of the springs and beyond is going to then put a stress on the axle where the support stops.

There are some pluses to a single axle but I'd never go back to one. Once one starts to take longer trips with a boat and pulls it further for those trips the boat seems to take on more weight and soon a single axle, unless one goes to one over 3500 lbs., and the tires will be carrying weight in excess of what they are designed for. Keep the boat relatively empty and that won't happen but it sure is easy to carry more and more in the boat if you become more inclined to cruise the boat. Even with a suburban as a tow vehicle I'd be hard pressed to carry less in the boat but others do,

Sumner
=======================================================================

1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...http://purplesagetradingpost.com/sumner/endeavour-main/endeavour-index.html
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas

 

[RussC]

Looks like someone negated most of the effect of the dropped axle with the addition of square tube spacers between it and the springs.

I added the 1" spacer to compensate for the 34 year old sagging springs. the keel was pretty close to the axle after I put the crown back in it.

 

[Sumner]

I added the 1" spacer to compensate for the 34 year old sagging springs. the keel was pretty close to the axle after I put the crown back in it.

Had the same problem with the orginal single axle's springs. Put on new springs and shackles (pretty cheap mod) and that raised the boat, but then still had to raise the bunks...

http://purplesagetradingpost.com/sumner/Macgregor Trips-2-Priest/08-09-8-priest-koot.html

... in Canada, after running down some roads under construction with big pot holes, and then finally gave up and added...

http://purplesagetradingpost.com/sumner/macgregor2/trailer-mods-8.html

... the second axle. I can't keep the boat empty . It is used as a camp trailer going to sailing destinations, so keep water in it and gas in the inboard tank if I think I can't find ethenol free gas where we are going and also both outboards are mounted on the back as I'm getting two old to lift the big one on and off.

Not sure of the current price, but getting a custom width axle made hasn't always been real expensive. One thing that can make it expensive is the freight and is the main reason ....

http://purplesagetradingpost.com/sumner/macgregor-trailer/trailer-mods-10.html

... I made my second axle. Only had to spend freight money on the spindles,

Sumner
=============================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas

 

[walt]

This is the clearance I have and its not that much but the boat has not bottomed out on the axle in its 26 years. But.. if you start heavily loading the boat, things escalate quickly (as you see from Sumners post). I did not even look into replacing the spings but that might also be a good thing to do every 25 years or so..

 

[centerline]

FYI, both the 2200 and 3500 axles from etrailer say this

• Bend in axle creates zero camber angle for even road-to-tread contact across the width of your trailer's tires.[/QUOTE)
• 
  
• Written as it is, this could be taken out of context... bending the axle CREATES a zero degree camber that would othewise be a negative camber on the loaded axle... also, I will never agree that a trailer axle needs toe in for the best tire wear or tracking.... It is NOT steerable/controlling axle..... preventing negative camber is the most important facter in proper tire wear on a towed axle... tow in on a trailer axle can compensate a little for a negative camber, for a bit more even wear across the tread faceof the tire, but it still causes scuffing and a greater rolling resistance.... but in the event one wants to have a little toe in on their cambered trailer axle, the spring seats can be removed, the axle rolled backwards an eighth of a turn and the seats welded back on top...

 

[walt]

bending the axle CREATES a zero degree camber that would othewise be a negative camber on the loaded axle...

This is the way I would interpret what is on the etrailer web site regarding "bend". The etrailer axle link also says this

Axle beam acts as part of your trailer's suspension system

https://www.etrailer.com/Trailer-Axles/Dexter/T3584F-EZ-8974.html

My trailer has "negitive camber" and I do get uneven wear. Some of you guys are expert welders but for most of us, welding on the axle of a trailer... Hmm.. I dont think Im good enough to accept the liability for the quality of my welding.. Im not a lawyer so dont know the actual risk.. but I will just side step this one.

Toe in - Toe out.. yikes.. is this yet another thing I need to check.. LOL.. (I dont think I will worry about this one - Im only remotely concerned about the caster being off a little as the tires expire before they wear out).
http://yospeed.com/wheel-alignment-explained-camber-caster-toe/

 

[RussC]

The reason cars have toe-in is because of the play in suspension and steering components. by adding initial toe-in, a cars tires will theoretically be pointed straight when under load and rolling down the highway. a trailer has no steerable suspension, so no, or at east very minimal, toe-in is needed. I like to shoot for 1/16" total toe in on a trailer (1/32" on each side) just to compensate for rolling resistance and wheel bearing play. seems to work for me.

 

[walt]

Committed now... just ordered all of this. I think I am getting over my urge to replace or do anything with that stock axle at all, just dont overload the boat/trailer.

 

[Sumner]

You will like the disc brakes!! Did you also get the hydraulic lines you will need? Here is a link to all you need...

https://www.etrailer.com/Trailer-Brakes/Titan/T4843100.html

......if they haven't filled the order the kit would be cheaper than parting it together and it has the bearings and seals and everything.

I got the actuator with the elect cut-out (was in the kit) and wired it to the backup lights, sometimes on a trip you end up backing up somewhere where having it is nice. If it isn't much more you could always wire it later, they still have the pin,

Sumner
==================================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas