Fuel line hose clamps

[cyberman]

Ok, so I went to remove the clamps and discovered they're "special". I assume they are the original clamps and thus, probably, the fuel lines are 25 years old. None of my sockets (metric or SAE worked) and on inspection they look different without the normal hex head.

I'm wondering if maybe this is the tool needed: https://www.tillmantools.com/baum-to...UaArPLEALw_wcB

The heads have a rounded, one-way castellation such that one can remove them with a flat-head screwdriver, but it's impossible to tighten them with a screwdriver.

Here's a picture, but it's hard to see since I have no macro mode on my camera (phone):



So, this opens up a world of questions starting with why did they do this? I've heard people frequently over-tighten small hose clamps, and this can cut the line and, with fuel, this could be disastrous.

System pressure is 3 bar (about 44 PSI) so my guess is that an ordinarily hose clamp could hold the pressure assuming it's torqued with care and not over-torqued. I check to make sure I've got fuel line rated at least 75 PSI, but assume that's nothing much to get to given the small diameter.

Experts: Please chime in here? Pretty please

[BimmerBreaker]

I have often replaced them with normal hoseclamps

[Randy Forbes]

I presume the factory never intended them to be reused, so I made a tool out of an old (Dodge Stealth cylinder-)-head bolt with an oval pocket to be able to tighten them back up again. It does the job.

The tool in your link looks appropriate, but $25.00 (plus shipping) would buy a handful of NEW clamps across your local BMW dealer's parts counter.

[cyberman]

Thanks for the quick answers. I was thinking standard, but stronger than average worm-gear type clamps with something other than that crazy head would work. It's nice to get some confirmation. The clamp otherwise looks like a typical worm-gear clamp. Opened up sufficiently to remove it with the the rubber still in place, it's about 5/8" and I'd guess it tightens to approximately 1/2" on the existing rubber. Torquing is going to have to be by "feel" on this one unless I can find some data.

Here's some information: https://www.normaamericasds.com/blog...lt-hose-clamps

But there's no info on how torque applied correlates to sealing pressure. I'll keep looking. Naa, it would be a difficult and risky calculation - lawyers would stop it.

So, Randy, you're correct. FCPEuro sells what looks like identical BMW clamps. The construction is the same as far as I can tell, but they have hex heads rather than whatever the original had. https://www.fcpeuro.com/products/bmw...mp-07129952104

The also sell an aftermarket version with a break-away head. The only problem with that is that I'd have to know the torque limit before the head breaks. I assume it's to prevent over-torquing. I'll ask about it. They could mean there is a built-in torque limit whereby it just spins once the limit is reached and that would be great.

[ProductUser]

I use hose clamps designed for fuel lines.

[Vintage42]

Would spring clamps work better?
Edit: Actually, I think I used these for my windshield washer hoses.

Spring Clamp 2.jpg

Spring Clamp 1.JPG

[cyberman]

I've backed off it for now. I'm pretty disheartened working in the heat, so I'm not taking on anything more other than get it back together and running. I believe the lines are accessible from under the car and I'll have plenty of time once the weather cools down to do stuff like that. But thanks for the tip.

I do wonder about a couple of things: what do all those vacuum lines to the injectors actually do? I mean why are they there? I'm curious about them.

And, the pipe mounted on the underside of the valve cover looks like it's supplied with oil via a hollow bolt. I don't see a seal between the top of the bolt and the mating pipe - am I missing something?

[ProductUser]

I'm with ya re the heat. It's going to hit 115f in Phoenix this weekend. My pool can boil lobsters at this time of the year

[cyberman]

Progress today: 4 hours of sweating over the engine bay and if my sweat was engine cleaner it would be great. All I got done was the install of all the little coolant hoses and 10 minutes to change out the idle control valve. Again, more cross-my-fingers-and-hope-it-works. This time, the hose rubber used is much thicker and lower durometer (softer) than I remembered. So, it seemed the hose clamps would never get tight and I compromised for fear of cutting the rubber. Too tight, too loose? God if I know, I have no feel for it.

But geez, 4 hours for all hoses except the two big main radiator hoses. If I worked in a shop, I'd probably get fired.

Tomorrow, the intake manifolds and the many connectors, starter wires, squid, oh my god. If this thing runs leak free and without throwing a code, it will be a miracle. For (name your deity)'s sake: two hoses just to go up to the little plate sandwiched between the two, count them two, intake manifolds... Took me a while to figure that out: I kept looking at the manifolds wondering where they plugged in. Endless senior moments and now they say COVID often does brain damage, which I need like another hole in the head.

[Vintage42]

... what do all those vacuum lines to the injectors actually do? I mean why are they there? I'm curious about them...

I read that they help fuel atomize around the injector tips at idle.

[cyberman]

Thanks, I'd guess the atomization is down in the cylinder and perhaps the vacuum is applied to pull mixture that blows back through the seal.

Hey, found something to do in the house with the AC on. Cut off all the valve cover bolt grommets and replaced with new. Maybe when I pull the seats I'll do the bushing job in the living room. Getting desperate here, fantasizing about taking some duct pipe and diverting some air to the garage.

[Vintage42]

Thanks, I'd guess the atomization is down in the cylinder and perhaps the vacuum is applied to pull mixture that blows back through the seal....

The atomization would be in the combustion chamber at the injector.
I think the vacuum is going the other way from what you said. I assume the vacuum hoses go to the injector bodies. I think the vacuum is pulled by the cylinder to suck air through the injector at the instant it squirts.

[cyberman]

Well, I found this explanation, but it still doesn't make sense to me. Several threads say that the engine seems to run fine when the hoses are just blocked off including this one. http://www.318ti.org/forum/showthread.php?t=28963

Wondering about everything and there is a lot to learn and understand here.

Like: I think there is a little pressure regulator on the end of the fuel rail and it has its own vacuum line, but that line is separate from the "tree" of vacuum lines going to the injectors. I wondered why one of the fuel lines is a solid connector going into the rail, whilst the other one has a short section of rubber. Now, and this is a guess, I think the solid connection is a steady high pressure line from the pump the other line is the return and it has lower pressure which would make sense considering there is a pressure regulator right there. The return probably doesn't operate at a very high pressure and the regulator just bleeds off when needed. Just a guess.

Note that in one of the old threads, the "tree" of preformed hoses cost $26 from BMW in 2006. My guess its 10X that now, but I'll check assuming it's still available. I may have to make my first visit to my local dealer to pick up the oil seal under the valve cover that I didn't notice I needed in any of the threads and guides I read. The problem with the seal is that it costs $10 online, but to get it here overnight costs another $30 and I think I'll need it by Sunday. Mistakes = experience for the next time.

[Charlie1990]

changing my fuel filter this week hopefully, reading all this was helpful, ty everyone, wish me luck

[Vintage42]

Well, I found this explanation, but it still doesn't make sense to me....

That explanation is for the single vacuum line to the pressure regulator on the fuel rail.
https://www.bimmerforums.com/forum/s...4#post11572344
I wonder if it applies to the vacuum lines on the four injectors.