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Sambar Corroded coolant pipes, another fixed.

Discussion in 'Subaru Sambar' started by hjvv/KS4, Jan 29, 2023.

  1. hjvv/KS4

    hjvv/KS4 New Member

    At the kind suggestion by Jigs n-fixtures to crank up a new thread for more visibility on what may become a more common "opportunity" as our Sambars mature. Please see below a copy/paste of my post earlier today on a useful earlier thread on this forum. An hour long test drive this afternoon, including some in-town low speed cruising, has not revealed leaks or further overheat issues.


    My 93 KS4 suffered some coolant loss from pinhole corrosion on exterior of motor to radiator inlet pipe under rearmost two of the three support clamps, and the smaller heater return line was quite thin at the same places. Removing the original pipes was done supporting under the frame on right side, liberating the spare tire from the carrier and carefully nipping off the 30 year old now screw-stuck wire hose clamps. After draining the radiator, patiently twisting and wiggling the hose connections free rewarded me with surprisingly intact and serviceable original looking molded hoses (to be replaced with new t-stat in fairer weather!) I found it is possible to thread the pipes forward and up under the cab floor enough to dip the rearmost end and slide it aft past the frame cross tube to then get the forward end under the tire carrier frame for another move or two to freedom. I was amazed and very pleased to look thru the shiny-clean tube bores, previous operators must have kept up on maintaining the fluids, no sediment showed in the radiator draining either. I cobbled up a replacement set of pipes using copper tubing and fittings from the local home and farm supply stores. Tubing in ID sizes of 3/4" ( 22mm OD) and 1/2" (15mm OD) are a very close match for the steel originals, I used "L" .06 wall vs the thinner .04 "M" tube for best strength. The pipes on my truck were about 58" overall, the main radiator supply needed addition of a Y reduced to a 1/2" branch for the heater feed. The radiator return pipe needed adding a T reduced down to 1/4" to fit the vent line. The heater return is just a straight 1/2" tube. I sweated all fitting joints using silver alloy solder as it is a good bit stronger than typical plumbing solder but can still be done in these sizes easily with a good propane torch. I figure I have spent about as much on copper parts as the OEM parts cost but skipped the shipping cost/delay. I refitted tubes to chassis and reconnected the hoses, now secured with Breeze clamps. I let the rear of the chassis down (left the front on jack stand to help air pockets moving toward radiator/expansion tank) and opened the high vent pugged line at the rearmost edge of the service cover opening to refill the cooling system using a Harbor Freight no-spill radiator funnel kit. A few hours of fabrication and same reassembling and filling/burping the cooling system test seems a success.
     

    Attached Files:

    Li'l White Sambar likes this.
  2. OhDeer

    OhDeer Active Member Supporting Member

    I guess my only concern would be the lack of a flange or whatever the little "nub" is called, but if it works then good!
     
  3. hjvv/KS4

    hjvv/KS4 New Member

    I did think about the worth of effort to add some extended surface area (think knurling) or a bit of a flare to the tube ends and just opted to be extra vigilant for seepage or any sliding off at the hoses.
    Figuring the nominal cross sectional areas I came up with force working to spit the hoses off as about 26.5 pounds for the 3/4" and 11.8 for the 1/2" tube fittings, that taking our radiator caps as typical the 15psi relief (my cap has no rating marked) if I ever flogged the Sambar hard enough to get er' that hot and lathered. I used Breeze band style hose clamps that look to be about 1/2" wide and well snugged up for a good grip. So far in rather cool testing weather, the temperature indicator has not gone past my "normal" as just below 9 o'clock.
     
  4. OhDeer

    OhDeer Active Member Supporting Member

    Yeah it's probably fine to take the "I'll keep an eye on it" approach. Coolant hoses always seem to be welded to the piping when you want to take them off anyway.
     
  5. hjvv/KS4

    hjvv/KS4 New Member

    Update, still no leak or cooling performance issues and no slipping of the hose attachment points.
    Last week was a real-world test, did my 48 mile early morning commute to work including 60-65 mph Baltimore beltway hustle. A good performance test was taking home a load of surplus storage racks (est 750-800lbs) on non-interstate road speeds of 50-60 (well, 40 up a few hills). Coolant gage never went over typical mid range, I,m calling this a success so far.
     
    Smollpp69 likes this.
  6. Marc Premil

    Marc Premil New Member

     
  7. Marc Premil

    Marc Premil New Member

    Your problem mimicked mine, exactly and I’m followingyour post, however, I cannot find a 3/4” x 3/4” x 1/2” wye (or branch) nor can I find the 3/4”x 3/4”x 1/4” tee, anywhere!
    My local hardware, box store, and farm supply stores were a washout. May you please tell me where you found these and or suggest an alternative?
     
  8. hjvv/KS4

    hjvv/KS4 New Member

    Hi Marc, It did take a bit of poking thru bins at a local edition of a chain farm supply called Rural King in Hanover, PA to come up with the combination I assembled. I had to get creative to make the two parts you ask about.
    Take a look at my images in the start of this thread to make sense of my recipe:
    [" I cobbled up a replacement set of pipes using copper tubing and fittings from the local home and farm supply stores. Tubing in ID sizes of 3/4" ( 22mm OD) and 1/2" (15mm OD) are a very close match for the steel originals, I used "L" .06 wall vs the thinner .04 "M" tube for best strength. The pipes on my truck were about 58" overall, the main radiator supply needed addition of a Y reduced to a 1/2" branch for the heater feed. The radiator return pipe needed adding a T reduced down to 1/4" to fit the vent line. The heater return is just a straight 1/2" tube. I sweated all fitting joints using silver alloy solder as it is a good bit stronger than typical plumbing solder but can still be done in these sizes easily with a good propane torch. "]

    My repair has been working great, no leaks or cooling/heating issues to date. Good luck and we will look forward to see how you do, this forum is a great resource that runs on our participation to share what we learn works or not.
     
    reggie98 likes this.
  9. reggie98

    reggie98 Member

    Be certain to cover/sleeve the copper where it's held to the frame by a steel clamp or electrolytic corrosion will pinhole your piping.
     
    Marc Premil likes this.
  10. hjvv/KS4

    hjvv/KS4 New Member

     
  11. hjvv/KS4

    hjvv/KS4 New Member

    Reggie, Absolutely correct, think my tubes failed just for that condition under the stock retaining clamps. I placed sections of split hose tubing to cushion and isolate the contact points.
     

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