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Topic: Getting ready to cut (Bulkhead)  (Read 1068 times) previous topic - next topic

Getting ready to cut (Bulkhead)

Cut my 4 pieces of 2X2 buy 11 inch  long safety bars.  Looking under the back first, I see on the driver side it looks like the 1 1/2 steel is doubled up on the first 20 inches then looks single width , Does the bolts go all the way through both layers of the 1 1/2 tubes , bolts must be at least 4 inches long ?  Where is the ply wood ?  What bolts go into the beams? What about the Front?  Thanks  Art
Art
1997 Prevost 40'
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Re: Getting ready to cut (Bulkhead)

Reply #1 –
Very safe feeling with the safety bars in place.  Did the torque test , Is that just setting torque on 21 ft pounds and only trying to tighten cw  ?  Checked back first and all good except on passenger side ,outer bolt broke and 3 in from that spun.  Front all good except 2 inter bolts in middle broke .    Should I just sister up a few bolts and call it good  ?
Art
1997 Prevost 40'
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Re: Getting ready to cut (Bulkhead)

Reply #2 –
Quote from: prevostart –
Very safe feeling with the safety bars in place.  Did the torque test , Is that just setting torque on 21 ft pounds and only trying to tighten cw  ?  Checked back first and all good except on passenger side ,outer bolt broke and 3 in from that spun.  Front all good except 2 inter bolts in middle broke .    Should I just sister up a few bolts and call it good  ?

Yes, if they don't move when the 21 ft lbs of torque applied, they are good.  And your choice on sistering or removing and thru bolting the broken ones/ones that just spun. 

On the ones that just spun I would see if you can back them out, then drill and thru bolt.

You might also clean and undercoat as I covered in the initial post on this to minimize water wicking up the threads in the future.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Getting ready to cut (Bulkhead)

Reply #3 –
Brett thanks for all your help on bulkhead repair.    Yesterday I worked on the back, I started on driver side and outer edge ,between 1st & 2nd bolt I drilled 1st access hole and drilled , put in first trough bolt which was a 4 inch long grade 8 . After that I went in between every 2nd bolt I installed 9 bolts.  Today I'm going to clean Prime & Paint. There isn't a gap where the 2 pieces come together so is paint OK or should I spray with undercoating ?  Do you think I can get away with fewer bolts on the front, I found only 2 broken bolts in the center.  Laying on the cold concrete all day isn't much fun, I'm sore all over.      Thanks  Art......
Art
1997 Prevost 40'
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Re: Getting ready to cut (Bulkhead)

Reply #4 –
Art,

My advice/opinion is that if you only have two broken bolts, particularly in the center, replace with thru bolts or sister them.  I would not go to a lot of additional work.

And I used undercoating vs paint because there is a tiny gap between the angle and the beam and I wanted to seal that area.  Undercoating is viscous enough to do that, I didn't think paint would work as well.  So basically, I undercoated from about 1/2" of the FG floor to the top of the vertical part of the angle beam AFTER masking off the outer 1/2 of the bolt heads so they can be rechecked  annually.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Getting ready to cut (Bulkhead)

Reply #5 –
Brett    When you put in the Heyco plugs , do you put any sealer on plug or do they stay in on their own ?........        Thanks    Art
Art
1997 Prevost 40'
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Re: Getting ready to cut (Bulkhead)

Reply #6 –
Art,

The Heyco plugs need no sealant-- they are designed to be waterproof as is (obviously when used with the correct diameter hole).

Note, Heyco also makes non-water proof plugs that I have seen used with BAD results.  I posted the correct part number for their largest waterproof plug in my write-up.  If memory serves, they are for 1 3/8" holes.  This is plenty large enough for installation of the flat piece I used next to the beam, the washer and nut and to allow wrench access to it.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Getting ready to cut (Bulkhead)

Reply #7 –
Brett,

I am generally pretty good at "techno" speak but I am confused by your mention of sistering.  Does this mean just adding additional bolts?
John Cooper
'91 GV 36'
Oshkosh chassis
Cat 3208T 300HP

Re: Getting ready to cut (Bulkhead)

Reply #8 –
John,

Yes, sistering is putting a good bolt on either side of a broken one.

Probably a term more used in the old wooden tall ships where that was a common method of reinforcing for a dry rotted frame member.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Getting ready to cut (Bulkhead)

Reply #9 –
Quote from: wolfe10 –
John,

Yes, sistering is putting a good bolt on either side of a broken one.

Probably a term more used in the old wooden tall ships where that was a common method of reinforcing for a dry rotted frame member.

Brett

It is also used in carpentry.
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: Getting ready to cut (Bulkhead)

Reply #10 –
I talked with a Registered Professional Engineer today about adding bolts vs. replacing them.  He thought that it would be much better to replace the broken bolts then to add additional holes in the angle iron and tubing.  The alternative would be to add a 1/8" thick x 1-1/2" wide metal strap to the back of the square tubing that would span the new bolt locations.

I assume that these bolts are attached for the full perimeter between the center section and the fore/aft sections.  If this is so, is there any chance the the other bolts have broken?  Based on what I have read here, it appears that some bolts have broken even though there is no rust jacking.
John Cooper
'91 GV 36'
Oshkosh chassis
Cat 3208T 300HP