shogun
01-31-2007, 09:54 PM
This was once written by Patrick C88 750, who drives an E32. That is probably worthwhile to post here too.:
Having used a few different kinds of hose clamps I settled to use the type of hose clamps that is made for fuel injection cars carried in local auto stores. The last few years the then new BMW 8mm fuel hoses at the firewall had experienced at least three times of leaking fuel on the road. I had used slotted clamps, BMW original clamps, BMW one-time clamps, and double (asorted) clamps. All had leaked at under the expansion tank.
There has been quite a few discussions of fuel hose clamps in this forum in the past. Generally, the slotted clamps are no-no because they bite into the rubber and gradually the rubber oozed out from thermal expansion/contraction and lost tightness. I don't know why the BMW clamps, while no slots, hadn't worked for me. Just as soon as I believe I found the most reliable clamp (below photo, right hand side), some of the local stores now carry a cheaper look-alike (photo, left hand side)that costs the same. That's why I want to post with the photo so people know which to choose in case they don't have luck with other clamps like me.
In below photo both are numbered 52F15 (for size 13-15 mm OD hose) but the cheaper version has duller finish on the band and comes with bolt with an ordinary head and material so cheap that the bolt will break when mildly torqued. The square nut is also thinner. If you can only buy this version you can change out the bolt with another Stainless steel bolt from hardware store, at least to eliminate that major weakness and potential failure on the road.
The good clamp has shinier finish (hard to compare if not side by side) but the tell-tale is the bolt which features an extended round section which is there so the rim of your 7-mm socket doesn't scrape on the clamp body as you tighten it down. The one bad design about this clamp is that the square nut is hold by a puny corner of sheet metal and the nut is easy to fly off somewhere down the engine when you insert bolt and try to engage the thread. Very frustrating.
To prevent that, you should dab a little of shoegoo, Homax welder adhesive, etc with a toothpick to secure the nut. Let cured overnight and the hose clamp is ready to go.
Attempting to finish off all firewall hose-related frustration I recently changed out that multi-section of hose and pipes into a pair of BMW 8mm fuel hose adding SS braided sleeves (Second photo below). I followed the suggestion of an archive posts here to drop the seven or eight anchors of the fuel pipes in front of driver side rear wheel and to open a hole in the driver front wheel well. That way I could easily gain access to the hose clamps hidden way down below the brake booster. To identify that the driver side pumps goes to the driver side bank, I removed the passenger side fuel pump relay (black 7-pin). The driver side engine bank should still start and idle. If not I would swap the two hoses.
http://members.roadfly.com/cheung1/fuelhose_clamps2.JPG
http://members.roadfly.com/cheung1/SS_braided_fuelhoses.jpg
Having used a few different kinds of hose clamps I settled to use the type of hose clamps that is made for fuel injection cars carried in local auto stores. The last few years the then new BMW 8mm fuel hoses at the firewall had experienced at least three times of leaking fuel on the road. I had used slotted clamps, BMW original clamps, BMW one-time clamps, and double (asorted) clamps. All had leaked at under the expansion tank.
There has been quite a few discussions of fuel hose clamps in this forum in the past. Generally, the slotted clamps are no-no because they bite into the rubber and gradually the rubber oozed out from thermal expansion/contraction and lost tightness. I don't know why the BMW clamps, while no slots, hadn't worked for me. Just as soon as I believe I found the most reliable clamp (below photo, right hand side), some of the local stores now carry a cheaper look-alike (photo, left hand side)that costs the same. That's why I want to post with the photo so people know which to choose in case they don't have luck with other clamps like me.
In below photo both are numbered 52F15 (for size 13-15 mm OD hose) but the cheaper version has duller finish on the band and comes with bolt with an ordinary head and material so cheap that the bolt will break when mildly torqued. The square nut is also thinner. If you can only buy this version you can change out the bolt with another Stainless steel bolt from hardware store, at least to eliminate that major weakness and potential failure on the road.
The good clamp has shinier finish (hard to compare if not side by side) but the tell-tale is the bolt which features an extended round section which is there so the rim of your 7-mm socket doesn't scrape on the clamp body as you tighten it down. The one bad design about this clamp is that the square nut is hold by a puny corner of sheet metal and the nut is easy to fly off somewhere down the engine when you insert bolt and try to engage the thread. Very frustrating.
To prevent that, you should dab a little of shoegoo, Homax welder adhesive, etc with a toothpick to secure the nut. Let cured overnight and the hose clamp is ready to go.
Attempting to finish off all firewall hose-related frustration I recently changed out that multi-section of hose and pipes into a pair of BMW 8mm fuel hose adding SS braided sleeves (Second photo below). I followed the suggestion of an archive posts here to drop the seven or eight anchors of the fuel pipes in front of driver side rear wheel and to open a hole in the driver front wheel well. That way I could easily gain access to the hose clamps hidden way down below the brake booster. To identify that the driver side pumps goes to the driver side bank, I removed the passenger side fuel pump relay (black 7-pin). The driver side engine bank should still start and idle. If not I would swap the two hoses.
http://members.roadfly.com/cheung1/fuelhose_clamps2.JPG
http://members.roadfly.com/cheung1/SS_braided_fuelhoses.jpg