idosubaru Posted March 18, 2017 Share Posted March 18, 2017 Rear bags leak slow with no holes. If you were to use a sealant to cover a rubber air suspension strut bag and wrap it with thin rubber what would you use? What is a strong adhesive but still pliable? Sikaflex? The Right Stuff. Something else non automotive? Also - what's a good way to hold the rubber tight to the strut after it's all assembled? A few ratchet straps would work but be clumsy. Maybe some coffee or other can cut in half and wrapped with straps would apply some even pressure? I did two today as a test with some Right Stuff and industrial rubber. I'm going to do another set as well with something else. Probably get some slightly thinner rubber than I used this time and look for a different adhesive. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 18, 2017 Share Posted March 18, 2017 Rubber cement? That's what you patch inner tubes with..... GD Link to comment Share on other sites More sharing options...
idosubaru Posted March 18, 2017 Author Share Posted March 18, 2017 Awesome. I'll look into it. Tires run like 40 psi and these systems are 100+. Think that matters? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 19, 2017 Share Posted March 19, 2017 I wouldn't think so - the rubber cement actually melts the pieces together - like plastic model glue. Make sure the patch extends like 3" out in all directions from the hole. They give you a little tool to scuff the rubber also so I would make sure you rough it up a bit around the patch. GD Link to comment Share on other sites More sharing options...
skishop69 Posted March 21, 2017 Share Posted March 21, 2017 I have a plan in place for this if I use up all my backup struts. Get vulcanizing patch cement from Napa. Get a motorcycle inner tube that's at least 20" in diameter and just slightly smaller than the circumference of the strut bag. Use a razor blade and cut it into 2" sections. Remove the strut and rig it so you can apply no more than 5psi to give it some rigidity and put it in the full extended position. Slide the inner tube sections on to the strut from the bottom. One for each step. Apply the vulcanizing cement to the top of the strut bag for a length of 2" per it's instructions. When it's 'dry', push the tube section up on to the strut bag when it goes on to the bag, you'll want to roll it so it rolls itself up into an o-ring shape. This will take some finessing to get it to roll up so the bottom edge of the cut comes in contact with the cement at it's edge. I suggest practicing with the strut dry/no cement first. The tube should stick to the cement so you just unroll it up on to the cemented portion of the bag. For the next and following sections, you only want to cement 1 3/4" of the bag and 1/4" of the piece you just installed. Put the next section on just like the first, but make sure you overlap 1/4" of it on to the previously installed section to ensure a good seal. Repeat the process until the bag is covered. Let it cure 24 hours before putting it back into service. I suppose you could get a vulcanized rubber sheet and try to wrap the bag with the vertical edges overlapping 1/4" but that gives a long vertical seam, and if/once a part of it fails, it will compromise the entire length and spread. It has to be vulcanized rubber like an inner tube or it will not bond properly and it will fail. Link to comment Share on other sites More sharing options...
idosubaru Posted March 21, 2017 Author Share Posted March 21, 2017 you seem to be addressing a failed strut - a tear or hole. i'm looking to address current struts before they fail. i'm looking for something that's a pliable filler and adhesive. i'd like to cover the entire strut with a pliable, flexible adhesive/sealant and then cover that with patches for added rigidity. the rear bags tend to crack in the same band (i've thrown away like 5-10 over the years) and will start leaking very slowly, not really a full on hole or tear. what kind of tube are you going to use that can support 110psi without any support since most are designed for use inside a tire? do you have a line on tubes that aren't prone to deterioate when exposed to the environment, UV, as they're generally designed to be covered (in a tire)? if the struts are kept operational they seem to hold up well. the ones i've stored have seemed to fail terribly even though they're stored inside a garage even. nearly all the rear air struts have started really small leaks, i mean like a bubble every minute kind of thing, not a full on tear. i guess the rears are made out of a thinner material? Link to comment Share on other sites More sharing options...
skishop69 Posted March 21, 2017 Share Posted March 21, 2017 UV shouldn't be an issue as the strut bags are in a 'covered' area. Exposure to the air (polutants) will be the killer, which escaped my plan. lol A good coating of silicone grease will take care of that. We've been using it for years on rubber components to protect them and it does an excellent job. As far as the pressure goes, the bag is contained in the upper sleeve, IIRC, so the pressure of the bag pushing on the sleeve will help reinforce the tube except for the spot where it rolls over itself when moving up and down. At least, that's my hope. If you're just addressing a few spots, I would still use the vulcanizing cement and then just go with smaller radial tire patches. Link to comment Share on other sites More sharing options...
idosubaru Posted March 21, 2017 Author Share Posted March 21, 2017 (edited) Do you know the difference between vulcanizing cement and rubber cement? Is it pliable ? You think the bags are similar materials as tires? It's not so much an area or spot so a patch won't work or would be temporary and recurring. It's an entire circumferential region of the bag. The rubber just degrades and very slowly leaks but doesn't completely fail (I mean so E do). I'm trying to address that. Maybe it's a northeast rust belt chemical thing mostly? I've seen like 10-20 rear struts do the same thing - degrade around 3" below the top rubber/metal juncture. One XT6 I had years ago (I've owned at least 20 of them) had some thick white stuff covering that area. I didn't think anything of it at the time so I'm not sure what it was. I have a set now covered entirely in The Right Stuff and so far they're holding. They were previously leaking. But I'd rather have a better adhesive/sealant and a top layer for support. Edited March 21, 2017 by grossgary Link to comment Share on other sites More sharing options...
idosubaru Posted March 21, 2017 Author Share Posted March 21, 2017 (edited) Duplicate Edited March 21, 2017 by grossgary Link to comment Share on other sites More sharing options...
ferp420 Posted March 21, 2017 Share Posted March 21, 2017 Fix a flat maybe or slime just a thought ive been using silicone ultra black alot for sealing up stuff like tires and water containers and rc car parts i wrap thead around the patch it holds up good to heat and presure and the thread give it substance and durabuility it is kinda like flexable fiberglass will it hold 100psi i dont know i wraped a glass vase ( sure it was ) that had broken and it held up till some one stepted on it and crushed the glass the silicone and thread kept its shape and still held water even with crunchy broken glass inside it diden leak so now i use it for everything after all a tire is just rubber and cords maybe tire black (that was the name brand of the rubber patch stuff we used at good year i patched/rebuilt a 2" hole in a side wall of a big truck tire with that stuff lasted the life of the tire) rubber with thread or twine Link to comment Share on other sites More sharing options...
idosubaru Posted March 21, 2017 Author Share Posted March 21, 2017 Silicon ultra black would be simple! People have used fix a flat stuff on other manufacturer air bags. One concern is it may plug air lines and the solenoid if it leaves the strut. No big deal if you don't care about the system functioning as normally intended Link to comment Share on other sites More sharing options...
idosubaru Posted March 21, 2017 Author Share Posted March 21, 2017 Thanks guys great suggestions, I thought folks would just make fun of me for not swapping. Lol Link to comment Share on other sites More sharing options...
skishop69 Posted March 21, 2017 Share Posted March 21, 2017 DO NOT use fixaflat. First, liquids do not compress. Second, in order for it to seal properly, it has to be circulated regularly. can't do that in an strut bag. Third, it will eat up solenoids and lines and/or plug them. Vulcanizing is a biochemical process by which strength and durability are increased by adding long chain polymers. Tires, inner tubes, strut bags and the likes are all vulcanized rubber. Vulcanizing rubber cement is designed to bond to vulcanized rubber on molecular level. Regular cement won't bond correctly. The issue you are trying to address would best fixed using my first solution. Covering the bag in this way will slow down or halt the bag degredation. Link to comment Share on other sites More sharing options...
idosubaru Posted March 22, 2017 Author Share Posted March 22, 2017 Why not cover the entire bag with cement and inner tube? Oh okay I thought the cement in tire patching was rubber cement, but you're saying they're different, got it. I wasn't really paying attention yet as I've just been trying to find patches. I'll do a test run with it on a completely blown sacrificial strut for practice working with it. I'm not using or recommending fix a flat type stuff. I was just relaying hands on experiences and data points, which I find helpful. Others have used it on Land Rover/Cadillacs. I'm unsure which brand/type fix a flat was used but it worked for years. I think they fill it at the bag and it didn't get back into the lines or cause issues (probably disconnect controller but I'm unsure?). I'm definitely not recommending it nor doing it. But I like real world practical experiences for data points. It could help someone limping a car along until they convert to conventional struts in the future and is affirmative towards the types of repairs you and i are discussing here. If a bad idea works then a good one should be pretty solid...so to speak. If anyone has seen fix a flat stuff used before, it would help the pool of data to share what vehicle, brand repair, what failed, how it was added and if the controller was disabled. Link to comment Share on other sites More sharing options...
skishop69 Posted March 22, 2017 Share Posted March 22, 2017 The reason you need to cut the tube into sections is that inner tubes are curved. Trying to slide a curved section on to a straight bag will result in 'baggy' spots on the outer curve edge that will bunch up and cause problems. I am hell bent on keeping my XT GL10 the way it came from the factory save for mods that are reversible so I put a lot of thought into the air suspension since there is nothing viable to work with as replacement parts. I can't even find a company willing to even attempt to fix the struts. Link to comment Share on other sites More sharing options...
idosubaru Posted March 22, 2017 Author Share Posted March 22, 2017 I hear you. I've owned XTs for 23 years, about 20 of them, and plan on keeping my current one til its wrecked or (hopefully not) rusted. Link to comment Share on other sites More sharing options...
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