Well I have discovered that my rear heater pipes are leaking and I am getting ready for a trip coming up soon. Don't want to take the chance of blowing them out further and getting stranded but don't have the time before the trip to do the job right. I have found other threads about the bypass at the firewall and some pics of what the hoses look like in the stock configuration but nothing showing the completed bypass. Can someone please post pics of this after it was done. Thanks.
Need Pics of Rear Heater Bypass at Firewall (1 Viewer)
- Thread starter toyman317
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I don't know if this will help, but I have some diagrams in one of my articles that might be useful...
ExpeditionLCMajorcoolingoverhaul
Here's the heater hose diagram....(detailed explaination in the article)
http://www.brian894x4.com/images/FZJ80coolingprojectx019.jpg
On the passenger side, the easiest solution would be to just go from the T fitting near the firewall to a straight fitting, but the driver's side doesn't make it easy without block off a hose port or running a by pass hose. I think for the driver's side, I would get a 90 degree heater hose and come straight out of the firewall and into lower section of the U pipe just to the left of the heater valve.
That's my suggestion after looking at the diagram. I suppose the quickest solution would be to run a heater hose from the left to right side, but that would just create one more hose and connection that could fail. (oops, just saw that you were looking for a quick fix, so this is probably the way to go)
ExpeditionLCMajorcoolingoverhaul
Here's the heater hose diagram....(detailed explaination in the article)
http://www.brian894x4.com/images/FZJ80coolingprojectx019.jpg
On the passenger side, the easiest solution would be to just go from the T fitting near the firewall to a straight fitting, but the driver's side doesn't make it easy without block off a hose port or running a by pass hose. I think for the driver's side, I would get a 90 degree heater hose and come straight out of the firewall and into lower section of the U pipe just to the left of the heater valve.
That's my suggestion after looking at the diagram. I suppose the quickest solution would be to run a heater hose from the left to right side, but that would just create one more hose and connection that could fail. (oops, just saw that you were looking for a quick fix, so this is probably the way to go)
There are a couple from when I bypassed the rear heater on my truck.
https://forum.ih8mud.com/80-series-tech/150466-rear-heat-bypass.html
https://forum.ih8mud.com/80-series-tech/150466-rear-heat-bypass.html
Good pics and good job, ibcrusn. Looks identical to mine, which makes me think that I did it right! Only thing I can add are these pics of mine plus the one showing the fittings - these are the fittings to remove. The 'T' shaped one is on the passenger side and the odd shaped one is on the driver's side. The capped fitting on the hose by the heater valve in pic 2 is my flushout connection. That is optional.
Edit: BTW, Brian (brian894x4; post # 2)has an excellent website with a lot of good info. I would highly recommend checking it out.
Edit: BTW, Brian (brian894x4; post # 2)has an excellent website with a lot of good info. I would highly recommend checking it out.
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Thanks Guys for the help. I believe I have it figured out then. I am hoping to eventually replace the pipes or reroute them in the future so this is just temporary. I actually have a spare set of pipes from a parts rig but I hear replacing those is a bear. It seems you would have to remove the cats to get to them and my cats are rusted pretty bad. Probably should just replace those as well while I am at it. Thanks again.
My reasons for bypass were just to simplify my heating system. Before I found MUD and before I knew what the PHH was, it started leaking on me, right before a major towing chore for my 80. It looked to me like it was coming from the conglomeration of heater hoses near the heater valve (I still hadn't seen the PHH). It was about a year ago and summertime, so with the towing trip bearing down on me, I said, screw this, and bypassed both heating systems (ran a hose from the top of the hard line above the PHH to the hard return line above the exhaust manifold). Well this took the pressure off the PHH since the closed heater valve was no longer restricting flow for that coolant path and my (still unknown to me) PHH stopped leaking for the trip. The tow trip went fine with the exception of not having a working heater/defroster. Here in the Pacific Northwest we can still need that system in the summer, especially at night. I ended up having to use the A/C to keep the windshield from fogging up to see and freezing out the
. After the trip I removed the bypass to find what I thought was a leaking heater hose. Surfing the web I found Brian894x4's excellent site where I discovered the PHH and also MUD. So with the wealth of info from both sites, I was able to successfully diagnose and replace my PHH. In doing this, I also made the decision to bypass the rear heating system. I've got ALL new hoses in my heating system with a silicone PHH and also the last hose near the water pump is silicone. I've evacuated all the coolant out of the rear heater lines and plugged them. I've removed the rear heater (beneath the front passenger seat). I've saved all the hardware in case I want to hook it up again. But it was rarely ever used and just a time bomb waiting to cripple my cooling system. It is purely a personal choice and for me, simplicity is beautiful. 
Resurrecting an old thread since I too found that my rear heater hard lines are rusting out and leaking under the vehicle. I have a trip planned and am wanting to bypass the rear heater. Can I just remove the T pipe and the funky T pipe and run regular heater hose? Or do a need something different for the "funky" pipe? And can I just use standard 5/8" hose? I would like to stop at the parts store on the way home today. TIA.
5/8 Gates Green Stripe or NAPA Gold Stripe works for the bypass, or really any quality 5/8 hose. Eliminating the rear heater is finicky only b/c the hoses enter the firewall where they are really hard to get to and tighten clamps, especially on DS, or was for me. If you search rear heater bypass, you'll find a wealth of additional info, but eliminating the fittings is part of the bypass. Careful with your heater valve; some will replace that as a 'while you're in there' item.
Good advice! I plan to get one ordered to have on hand. My 24 yr old rig is not bulletproof....not quite...lol
Patience, determination, perseverance and hold your mouth right while leaning across the engine. A few choice adult words and even choicer adult beverages might help too. I think I actually laid across the engine and attacked it from all angles until I found the right combo, leaning my weight on my right arm on the valve cover while my left turned the socket on a perfectly pre-positioned clamp. It helps to lube the nipples and inside the hose to get them on the firewall, but doesnt help with the clamps. It was a booger.
Edit: There is a specific Napa number for the DS hose that connects the hard pipe that comes up from the PHH. It made things easier with a little trimming. I found it in one of the posts, but no idea what the PN was ATM.
Edit: There is a specific Napa number for the DS hose that connects the hard pipe that comes up from the PHH. It made things easier with a little trimming. I found it in one of the posts, but no idea what the PN was ATM.
A trick I use is 2" x 6" boards long enough to reach from my ARB bull bar to the cowl between engine compartment and windshield. Lay or put your weight on these instead of engine parts which are hot, sharp and brittle. Move them to where you need them for support.
Got it done! I took off the control valve and the hoses going to and from it. Made the bottom hoses / pipe more accessible. Still was a pain but is now done. Doesn't appear to leak either 
I stopped by Napa and got a generic 5/8" 90 degree cut to fit hose to replace the funky pipe. And just used a piece of bulk 5/8" hose for the passenger side. On to the next project! Thanks everyone.
I stopped by Napa and got a generic 5/8" 90 degree cut to fit hose to replace the funky pipe. And just used a piece of bulk 5/8" hose for the passenger side. On to the next project! Thanks everyone.
Help me understand... does this bypass eliminate the rear heat or the front floor heat?
I'd like to keep the front floor heat intact.
I'd like to keep the front floor heat intact.
It bypasses the rear heat. Eliminating it requires removing rear heater core under PS front seat and associated heater plumbing running by the cat, and then plugging/repairing the holes. I left mine intact, just bypassed due to coolant leaks and corroded original pipe/hoses to reduce chance of a coolant leak breakdown. Next owner, if I ever sell, can always fix and use it if they feel it's needed.
