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Radar Arch Nuts Loose

Posted: October 11th, 2017, 9:17 am
by feeez
The radar arch attachment nuts and lock washers on our 350 Mariner are located behind 4 access panels on the arch. I recently decided to replace the plastic screws that hold the panels in place with stainless as some of the heads had broken off.

After removing the panels I noticed that 2 of the 4 nuts were loose to the point that the lock washer was no longer compressed. One of them I could move by hand.

Just thought I would pass this along.

Cheers
Fraser

Re: Radar Arch Nuts Loose

Posted: October 11th, 2017, 9:55 pm
by daveS
Thanks Feeez
I will check mine

Re: Radar Arch Nuts Loose

Posted: October 12th, 2017, 4:30 am
by mjk1040
Just did the same thing on our 355! Everyone needed to be tightened. What size and type of SS machine bolts did u replace the plastic one with? I replaced the broken ones with new plastic ones, but now wish I went to SS ones.

Re: Radar Arch Nuts Loose

Posted: October 13th, 2017, 11:41 am
by feeez
mjk1040 wrote:Source of the post Just did the same thing on our 355! Everyone needed to be tightened. What size and type of SS machine bolts did u replace the plastic one with? I replaced the broken ones with new plastic ones, but now wish I went to SS ones.


I believe the appropriate replacement was 10-24/ 3/4" SS machine screw.

Cheers
Fraser

Re: Radar Arch Nuts Loose

Posted: October 13th, 2017, 12:17 pm
by nightsky
Thanks for the heads up. I was in behind that access panel recently to run wires from a solar panel I installed on the hard top. Saw those bolts but didn't think to check them. I will do so. On the issue of SS nuts and bolts for the access panel, mine has them, but I found that the stainless reacts with the aluminum of the panel and the arch and several of the threads on the aluminum corroded away. Perhaps the plastic is a better choice just for this reason.

Re: Radar Arch Nuts Loose

Posted: October 13th, 2017, 5:36 pm
by Viper
nightsky wrote:Source of the post....On the issue of SS nuts and bolts for the access panel, mine has them, but I found that the stainless reacts with the aluminum of the panel and the arch and several of the threads on the aluminum corroded away. Perhaps the plastic is a better choice just for this reason.


BINGO! that's why they use plastic. You can use stainless steel but you must take measures to prevent galvanic corrosion. I use Tef-Gel on the threads when fastening dissimilar metals.
http://www.tefgel.com/contain.php?param=tefgel_price

Re: Radar Arch Nuts Loose

Posted: October 15th, 2017, 5:11 pm
by mjk1040
Ah! Ha! That solves the $60K question why they used plastic in the first place.

Re: Radar Arch Nuts Loose

Posted: October 18th, 2017, 10:14 am
by bud37
So Fraser, I finally got tired of looking at the missing screws on ours , thanks you are responsible here :-D .......well they were a mix of plastic with heads, headless and SS with the heads painted white, the SS were all fine but the plastic I replaced with stainless and will paint them white next year...the bolt was fine....interesting as there is no gasket here and you can see some evidence of small amounts on moisture getting in there, so I caulked the seam with some simple caulk and I think I will make gaskets next year to seal them and make removal easy......it is possible there could be another reason for the plastic perhaps....cost...... :beergood:

Re: Radar Arch Nuts Loose

Posted: October 18th, 2017, 12:31 pm
by feeez
bud37 wrote:Source of the post interesting as there is no gasket here and you can see some evidence of small amounts on moisture getting in there, so I caulked the seam with some simple caulk and I think I will make gaskets next year to seal them and make removal easy......it is possible there could be another reason for the plastic perhaps....cost...... :beergood:


I had the same feeling about that when I put them back together. There was a real build up of green yuck between the plates and the arch so rain water it making its way in there for sure.

Fraser