View Full Version : Axle U-Bolts

05-06-2013, 08:42 AM
I have 1998 205 and want to put 15" rims on it. To do so I decided to lift the trailer a bit. Its in storage right now and not overly convenient to get to. I was down there this weekend and measured the length of the u-bolts but forgot to get the width :uglyhamme . Has anyone done this or have the boat/trailer handy to get me the u-bolt dimensions? Thanks.

05-06-2013, 11:14 AM
you and i are on the same page right now, i just got done installing in new springs and the thing is to low now so i am puting in 1" blocks to lift it. my axles are square and the u bolts that i am looking at are http://www.grainger.com/Grainger/U-Bolt-5YY42?Pid=search

05-06-2013, 04:33 PM
Are the u-bolts 3/8? I thought mine looked like 7/16.

05-06-2013, 05:22 PM
now that you said that i think you are right, i will check later.

05-08-2013, 09:49 PM
Have you had a chance to investigate the u-bolts anymore? I finished up my blocks today, so now I just need to figure out my u-bolts. Might have to go take a closer look at the boat this weekend if no one has info.

05-09-2013, 09:18 AM
Just to show what I am working on I have attached some pictures of the blocks I am using. Started with 1-3/4" x 2" blocks that are 2"-3" long. Drilled a pilot hole all the way through in the center. Then drilled it out to 5/16 (the drill size for tapping a 3/8 -16 hole. Then drilled the other side out to 11/16 deep enough that the head of a bolt would fit in it (centering bolt in spring has a 9/16" head). I tapped the small hole to 3/8 -16. Now I should be able to put a bolt in the threaded portion, and have the centering bolt in the springs fit on the top, and be good to go. I will probably weld the block to the trailer also. Now I just need to get some u-bolts that are a couple inches longer.

05-09-2013, 10:22 AM
i am really confused by your block design, where are you welding them to. i understand making blocks that go between the spring and the axle but not the bolting and welding part. as for the u bolts i had a local shop make them for me. they are 9/16 thread 2" wide by 7.5" tall. when i get them today i will take some pictures and post them along with the price if you want i can give you the contact so you can order also. as for the top plates i am going to waterjet some new ones out of 3/8 plate.

05-09-2013, 11:02 AM
Seems like a pretty huge block you have there.

Are you planning to bolt it to the spring pack or just a block underneath? For my Blazer, there is a "1-Inch zero rate" spring which acts like another leaf in the spring pack but lifts it another inch (and bolts to the existing spring pack.) It also has a centering pin. These are 2.5" wide though and I don't know how wide our trailer leafs are.


05-09-2013, 11:30 AM
Good to know on the u-bolts. I have been searching around and asking if anyone knew of a local shop that could custom make some u-bolts for me, but I haven't had any luck as of yet. I think I should be able to get bolts and plates online somewhere if need be.

As for the blocks, the 3/8 tapped hole will get a bolt threaded into it to replicate the head of the centering bolt on the springs. It doesn't actually bolt anything together, just keeps the block located where it should be. The actual head of the centering bolt will then rest in the 11/16 hole drilled on the top side. This should keep everything lined up as it was before. Welding the block to the trailer would just be added strength, since lifting the trailer will add more torque to that joint.

05-09-2013, 11:38 AM
The blocks will raise it 2" and are 1-3/4" wide to match the leafs. They might be longer than they need to be, but I don't know that it matters. They will not be bolted directly to the leaf springs.

In hind sight, it probably wouldn't have cost much (if any) more to just measure the free dimensions of the springs and get some with higher arch. At this point its a matter of pride and making this work safely.

05-09-2013, 04:46 PM
ok, i get it now. i am still waiting on UPS they are not really worried about time frame around here for some reason. also the u-bolts that i am getting are supposed to come with nuts and washers. i will be out of town for 2 weeks but when i get back i will get this all done and take some pictures.

05-10-2013, 05:29 PM
they showed up, 8 of them with bolts and washers.

05-10-2013, 06:06 PM
U bolts from Grainger were just zinc plated, I would go with stainless. Here is the ones I sell: https://www.mscdirect.com/product/82687955

Same specs 2" wide 3/8-16 thread.

05-10-2013, 09:15 PM
the ones I got are 9/16 thread and are not stainless but really how often is the trailer in the water. I saw those and I did not trust the 3/8-16 size, nothing against what you sell.

05-14-2013, 11:39 AM
well here is a better option than having them made.

05-14-2013, 12:41 PM
another option is to buy the lifting blocks and u-bolts from california trailer. I tried to find springs with different height but could not readily find any so I bought new springs with same curve as original which gave it a little lift and then added the blocks. I was having problem with the prop guard hitting the driveway every time I pulled it out of the garage. Cal trailer was the only place I could find lifting blocks on line that indicated they would work with the mastercraft trailer.

03-06-2014, 10:10 PM
Will this work on a tandem trailer, 2003 Anniv. with 14 inch wheels. Trailer is at the and I can't inspect to see the springs and axle. Thanks in advance, I only need an inch.

MasterCraft 4 Ever
03-07-2014, 09:43 AM
I have always gone to a place that replaces springs or sells them (not a box store). When I was a diesel mechanic we brought a representative sample of what we needed. For example round top, square top, diameter and length. They would bend them up for us right there on site. Mutual Wheel in Rockford, Illinois used to do this. Ask a heavy truck repair place where you could get U-bolts bent for your application. Easier then looking on dozens of websites trying to find a perfect match.