Hydraulic Lines

Issues with shocks/springs, tires, steering box, stopping, etc.
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rmel
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Location: Woodside, CA
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Hydraulic Lines

Post by rmel »

Here's something to watch out for -- rub wear on the hydraulic lines.

There are three lines that run from the bottom of the air tunnel, under
and between the front diff and bottom of engine, then along the tube to
the end points of the 4x4, rear locker, and rear Brakes.

The PIX below is the Brake line, which apparently was rubbing up against the
Engine and eventually wore thin enough to burst. You can see the burst along
the lengthwise direction.
Brake-line.JPG
Brake-line.JPG (854.51 KiB) Viewed 3652 times
This is the 2'nd time this has happened :cry: The first time I ran into this problem
was with the 4x4 locker line. This was several years ago before affordable
Inspection cameras were available e.g. from Harbor Freight -- you just can't see in this
area W/O one unless you pull the engine :shock:

My hunch is someone before me did some work in this area and messed it up, so if
you have lines that have not been tampered with you might be fine -- but if you have
a camera you may want to peek in there and make sure.

Dono what's worse loosing lockers on a challenging trail or your rear brakes :?
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712MK

Driver: Ron // KO0Q
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TechMOGogy
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Location: Ontario, Canada

Re: Hydraulic Lines

Post by TechMOGogy »

Good to know
Thx for posting
72 Pathfinder | 75 710M 2.7i | 96 350GDT Worker
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GadgetPhreak
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Re: Hydraulic Lines

Post by GadgetPhreak »

Thanks for sharing, I'll be picking up a camera and doing some investigative work this weekend while swapping out my front shocks and taking care of a few other odds and ends...
King County Search & Rescue | Regional Special Vehicles Unit
1972 710M - Building up for SAR use
Follow my build, learn more, or contact me: http://www.sarpinz.com
sprbxr
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Re: Hydraulic Lines

Post by sprbxr »

Im fixing that exact issue on my Pinz. After fighting with a few seized fittings, I decided the best way to replace all the lines would be to remove the body from the chassis. Took a little less than 2 hrs to pull the body.
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rmel
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Re: Hydraulic Lines

Post by rmel »

I am starting to see spares for the longer Hydraulic lines becoming harder to get.
These are the lines that run from the front distribution block to the rear of the
truck for rear Brake, and locker control.

I am setting myself up to fab my own lines, here's what I have learned and recommend.

First, DO NOT toss your old tubing nuts, these are not easy to come by.

The flaring and tubing used: 6mm steel tubing, double 45 degree SAE flare. I recommend
using 6mm x .71mm Cunifer (Copper-Nickle) brake line, it is far more ductile than steel thus
easy to form, burst strength exceeds DOT requirements. Common on Porche.

You will need a very high quality flaring tool to form these seats. I have acquired a flaring
tool made in the UK, you can get one at http://www.fedhillusa.com/, you will also
need a 6mm die set. Fedhill is currently out of stock. Earl's Plumbing (Holly), has a tool set
but it is much more expensive.

Tubing nuts are: M12 x 1.0 thread, for 6mm tubing, seated for a double 45 SAE flare.
The first 2mm of the nut has a relief and that is important for proper sealing. Pictures below
show the 45 degree seat, and double flare tubing.

The one flare type that I wanted to make sure was not used here is a 37 degree double AN flare.
From the picture below you can see the nut seat is a perfect 45. From what I can tell, the metric
nuts used on the Pinz are hard to source as it is far more common for Metric tubing nuts to use a
Bubble seat not SAE -- keep the old nuts.
IMG_2854.jpg
IMG_2854.jpg (168.83 KiB) Viewed 896 times
IMG_2855.jpg
IMG_2855.jpg (96.95 KiB) Viewed 896 times
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712MK

Driver: Ron // KO0Q
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