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Discussion Starter #1
Found the right hinge mount of my trunk cracked away from the lower casing on the weekend. The whole base of the hinge support has parted company from the case (these are the Don Muddiman armrest hinges.... but I'm not blaming them for the cracking).

Anyone have an experienced opinion on whether Plastex or JB Weld (or something else?) is best to recreate the mounting point?

At the moment I'm inclining toward using Plastex with some fibreglass cloth reinforcement from what I've seen on the youtube videos... although I'd have to get that shipped from the US via Ebay as not available locally as far as I can find.

 

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Enjoy The Ride
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Permatex makes Permaoxy. It bonds ABS, Acrylic, Fiberglass, PVC, Vinyl, Steel & other materials. I don't know if it is strong enough for your repair.
 

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I had the best results using PC7 and a thin layer of tin punch metal on the side that doesn't show.

My problem was the front fender cracking and it has a lot of flex while riding. I did try epoxy and fiberglass but it failed within a few months.

http://www.pcepoxy.com/our-products/paste-epoxies/pc-7.php

Ron
 

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I have experience with exactly the same break on my newly-purchased 2003. Seems that this is one of the weak links of the bike, caused either by overloading the small rack on the top case lid, or by letting the lid 'overextend' itself while opening.

I was fortunate enough to have the hinge break cleanly. Though it was very ugly, and a couple of small pieces fell into the trunk body, the remainder was a good, clean fit back together.

Short answer is that I took a Dremel and and ground off the lower rivets, which separated the hinge from the trunk body, so I could work with just the plastic. Called the very helpful people at JB to confirm that this glue would be appropriate for the repair. Was answered in the affirmative, but the tech made it VERY CLEAR that 90% of adhesion failures were due to improper preparation of the parts to be glued. Couldn't stress enough that the parts were NOT to be cleaned with alcohol, as it leaves a residue which weakens the bond. Follow the directions and you'll be fine.

Just a note: In order to prevent hyper-extension of the lid in the future, I went to the local sporting goods store, bought a piece of 16" or 18" (I forget which) stainless cable fishing leader (30# test) and attached it along side the nylon trunk strap. Folds easily upon itself, and prevents the top from opening too wide.

The whole repair looks good and has held beautifully.
 

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I may have a bottom half of a top case, or know of someone who does. Yours for price of actual shipping if I can get my hands on it for you.
 

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Discussion Starter #6
Thanks all.

Tony, I think shipping costs on that kind of weight might be a bit prohibitive, however I won't knock the generous offer back just yet..... :)... just put it on hold!
Think I'll try the repair first. I'll probably reinforce both sides as its likely the break has put undue pressure on the other side too.

If I wind up getting the trunk I"ll go the whole hog and get you to ship me some cheap (compared to Oz prices) tyres too in the same box! ;)
 

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If you do a search for "top case hinge repair" and look in the thread started by marc the beginning of last year, you will find my post and how I fixed mine. Any questions, pm me.

Ray
 

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cws said:
Thanks all.

Tony, I think shipping costs on that kind of weight might be a bit prohibitive, however I won't knock the generous offer back just yet..... :)... just put it on hold!
Think I'll try the repair first. I'll probably reinforce both sides as its likely the break has put undue pressure on the other side too.

If I wind up getting the trunk I"ll go the whole hog and get you to ship me some cheap (compared to Oz prices) tyres too in the same box! ;)
Whatever works, mate, no worries!

You have the address, just drop me an email or a Skype to let me know what is coming and how quickly you need it to you.
 

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Discussion Starter #9
RiderRay said:
If you do a search for "top case hinge repair" and look in the thread started by marc the beginning of last year, you will find my post and how I fixed mine. Any questions, pm me.

Ray
Thx Ray, looks pretty much identical to mine, right down to Don's hinge.
I'll pull it all apart one weekend and see if I can rebuild the fixing points from underneath with Plastex, re-inforced with fibreglass cloth, and maybe a good dose of JB weld for extra support.
I'll keep your fix in mind also if the repaired support doesn't seem like it'll take the weight/pressure/vibrations.

cheers gents!
 

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I've had mixed results for plastex. Not the easiest to apply. I went to fix the nut inserts on the handlebar plastic covers with plastex.... one was ok, other failed right away so now trying JB weld on that one. Leaving it overnight. See how it does.

My lower trunk hinge support is cracked too, but I figured it's from the left side hit the bike had before I owned it. I used plastex for now.

But I have a replacement champagne color lower trunk coming from www.beemerboneyard.com for $288 with shipping charges in.

I may reinforce the replacement lower trunk under the hinge area with jb weld before I install it as it seems like a weak point. Lot of stress there from the passenger leaning on it and luggage weight.
 

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Dragonwing said:
... Couldn't stress enough that the parts were NOT to be cleaned with alcohol, as it leaves a residue which weakens the bond. Follow the directions and you'll be fine....
That's interesting. I always thought alcohol was good to use because it didn't leave any residue after drying/evaporating. :confused:

Matter of fact, when I was learning high-reliability soldering techniques in the Air Force, it seems we used some form of alcohol to remove the protective coating from the various conductors and components because of it's drying properties, and these were NASA's standards. Hmmmm. Maybe that's the reason their heat shields were falling off their space shuttles. :rolleyes:
 

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Discussion Starter #13
Dragonwing/ said:
"parts were NOT to be cleaned with alcohol"
probably meant "don't spill your beer on the parts while working." :rolleyes:
Roughing up whats left of the surface with a Dremel or sandpaper will probably give a good enough adhesive point without using an alcohol cleaner.
I'll find out once the Plastex arrives. JB Weld Marine came in the post through the week.
 

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cws said:
probably meant "don't spill your beer on the parts while working." :rolleyes:
Roughing up whats left of the surface with a Dremel or sandpaper will probably give a good enough adhesive point without using an alcohol cleaner.
I'll find out once the Plastex arrives. JB Weld Marine came in the post through the week.
Oh, definitely don't spill your :beer:
That's considered alcohol abuse. :eek:
 

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Discussion Starter #15 (Edited)
Repairs completed.. it was a multi-part task:
1. remove top-box (and at same time find where clueless BMW techs had hard-rewired my GPS power supply to rear powerlet... had to cut wires and install connectors for future re-connection)
2. dis-assemble the hinge from broken plastic section
3. use JB Weld to stick the broken plastic back to the top-box
4. use Plastex and fibreglass cloth to rebuild the missing plastic sections
5. re-attach hinge
6. use JB Weld to strengthen all areas of the break and provide additional support for the hinge, also JB-welded underneath the good hinge to give extra strength just in case
7. spray paint over the new hinge rivets and plastex parts to hide colour mismatch
8. re-install the top-box light switch
9. re-install top box, insert plates and wiring..... check all works OK.
good to go!
Fiddly job, and not too beautiful a finish due to working late at night to get it done. At least its hidden most of the time.

Some pics here if you're bored and got nothing better to look at..... ;)


like the 2nd-hand Aston Martin ad... :eek::clapping:
 

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After trying silicon cement with little lasting power, I tried again looking at it in a different way. The problem is the lifting up of the hinge when the lid is opened. From behind the left panel, (power outlet) next to the backrest, I drilled a small hole in the middle of the 2 middle plastic supports. I ran tie wraps through the holes to the lower metal hinge back plate and fastened them tightly. Holds the hinge down very well. Hope it passes the test of time. If a tie wrap breaks, it's easy enough to replace and there's not mess involved with all the epoxy/cements that were starting to build up, but not work for very long. This may also be viewed as an easy to do preemptive task before the cracking begins.
I can't upload a pic, so if you want to see it, PM me for an emailed view.

HTH,
Jer
 

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After the epoxy cures use a long worm drive hose clamp covered with shrink tube to keep the
lower part of the hinge in place.
 

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The OEM top box rack is rated to 10 lbs IIRC.
I certainly use all that, frequently, but no failures to date.
I did shorten the retractable strap very early on so the lid
just opens about 90º. Enough to stay open but not too much.
Maybe that helps.
Have used JB Weld on another project on the ABS tupperware
so far with good results.
 

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I've used regular black ABS glue (like found in a plumbing dept) and fiberglass cloth. You put a layer of ABS glue down, lay the fiberglass sheets on it and then put another layer of ABS glue. When this dries, it's very hard and permanent. I repaired a previous top case (on another bike) and it held fine up until I sold it. Makes a very strong bond on ABS plastics. Just an idea.

Sammy
 

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All I did was make two holes and tightened two tie-wraps. I'm sure there are many was to "skin this cat", just offering up mine. Seems a lot easier, so I'm including it. Wish I was better/more patient at using epoxies, sealants or cements. I tended to rush the job, so I just wanted a simple solution.

HTH,
Jer
 
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