1994 940GL with Bosch fuel system

I'm going to embark on the job of changing my fuel filter and replacing the crossover pipe between filter and pump which is a copper pipe and all twisted up. (Doesn't look original - uses a male/male nipple threaded into the filter, and the copper crossover pipe has female/female fittings)

I've read in other postings that air tools are the best idea as regards fuel line fittings (banjo bolts). Presumably this is because they do things up tight nice and quickly without the same risk of twisting the filter or the fuel line around. Correct ?

I've borrowed an impact driver that looks like the one pictured on this link:

http://www.toolprice.com/product/6786F

Is this the sort of tool I should be using ?
The box on mine quotes a ULT Torque at 90psi of 75 ft lbs
What does ULT torque mean ?

75 ft lbs seems a lot for a fuel line fitting. What is the torque recommendation on the banjo bolts into the fuel filter ?

I assume I can use the little adjuster wheel on the driver to reduce the torque (?) but how do I know what torque setting it is set to ? (The wheel has a scale of 0-8)

My other concern is of fuel squirting out everywhere when I loosen the fuel line fittings. I'm going to use a Mityvac and apply a vacuum to the fuel pressure regulator - that should depressurise the fuel line shouldn't it ?
How much fuel should then leak out ?


John Marshall
1994 940GL
Christchurch NZ

Dear John,

Good a.m. and may this find you well. Further to a post below, if you use impact tools on the fuel filter fitting, you MUST disconnect the negative battery cable clamp from the terminal.

The reason: to avoid triggering the airbag(s). The SRS (airbag) sensor is just above the fuel filter housing, and if you don't disconnect the negative cable clamp from the battery terminal, the shocks from the impact wrench could trigger the airbag.

While you won't be in harm's way, a replacement airbag will cost about NZ$1,500 (US$1,000).

Yours faithfully,

spook

Reasons to use impact tool are not for brute strength, but to allow inertia to work in your favor. If you have wrenches that fit the filter and the banjo bolt very well, squeezing them together will overcome. As "dead simple" as one helper suggests this is, it has caused grief to many, probably not as skilled as he is. The bolt was installed with an impact tool at the factory 10 years ago. Use the hand tools to put it back on.

NO MAN, NO AIR TOOLS ON THE FUEL FILTER OR ANY OTHER PART OF THE FUEL SYSTEM!

Normal wrenches will work fine - it's a dead simple job to replace the filter.

If you use air tools, don't have the ignition turned on to listen to the radio.
The sensor for the SRS system is located pretty close to where you'll be working.


Mike

Personally I would not use an air wrench to change a fuel filter.
To keep things from twisting/rotating, the best way is to use a 2nd wrench - 1 wrench to hold things still and another to tighten the bolts. The fuel filter has a bolt-head shape cast into each end of it for this purpose.

As for leaking fuel, if you depressurize the fuel system first, then no fuel will "squirt" out of the loosened fittings, however you will still lose some fuel to gravity since the filter is the lowest point in the system. Maybe 1/2 - 1 pint? If you have one of those oil change pans just put that under the filter after you loosen it up.

--
Matt L. -- Cary, NC -- '91 740 wagon

Dear John,

Good p.m. and may this find you well. According to the Volvo pocket data booklet, Cars - 700,850,900 (1991-1996), p.32, the torque specification for Fuel Filter (all B200/230, 204/234 engines) is:
20-35 nM; 15-26 pound/feet.

This seems like a very wide range to me, so I'd go for something in the middle, i.e., about 28nM / 20-21 pound feet.

I note that on a Rex/Regina system, the torque spec is 27nM / 20 pound/feet (see p. 34, of the same publication).

Good luck with this.

Were you able to find a source of bulb grease (dielectric grease)?

Yours faithfully,

spook