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tatra 813 new owner

duncan

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As far as Ive seen so far the compressor is doing fine. The air shutoff valve in the back needs new seals, it seems to shut off at random. I can block it with my finger and it closes for a few minutes, then it starts blowing air again.

Also one of the air tanks has a broken seal so its leaking all the time.

Have my work cut out for me for the next week!
 

duncan

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Yeehaw, did a little more driving today. Went over to the car wash :-D to clean the parts of the truck I couldnt reach when the bed was still on. Got me kicked out withing 10 minutes :twisted: but got most of it done.

Every minute I drive it the engine starts running better, gears change better, etc. It's all coming to life now. Got the thing out of low gearing too!
Will change the clutch fluid again to a lower SAE now, it's running a bit too heavy for my liking.
The wheels seem to slowly roll into shape again too, ride is not as bouncy as it was the first miles.

Ow and lastly, I offroaded it for a bit. Someone parked his car so stupid I couldnt pass over the road (I live in a city, that stuff happens). Went for the pavement, then over the grass, and left a beatiful threadmark. It looks like 4 angry tractors chased eachother over the field :-D

I'm loving it!
 

EZFEED

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Too cool Duncan!!!:-D You need to take some pics and videos next outing!

Have you cleaned out the crankcase and axles with diesel? Its good to do this before your next oil change, drain a gallon of oil out and add a gallon of diesel and it will help break up any sludge in the engine. Also do it in our tranny and axles too. Really does a job cleaning!

Hows your air pressure doing?
 

duncan

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Will do some pics next week I think.

So you're saying I should replace some oil with diesel in the engine, and run it like that until the next full oil change?

Air wise, I fixed the leaking air tank by replacing the seals. Now getting about 4 to 4.5 bar. Next major leak is the air pressure regulator which I will overhaul next week. Hopefully it just needs new seals too. Then the.. whatever you call the air distribution valve that separates different air systems (front brakes, rear brakes, tailer brakes, etc)... is leaking slightly too. Again looks like seals.

lastly I couldnt resist taking her for a spin again. Found a deconstruction site and trashed it. Drew quite a crowd. Helluva fun! More next week :-D
 

cranetruck

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Will do some pics next week I think.

So you're saying I should replace some oil with diesel in the engine, and run it like that until the next full oil change?........
I'm sure EZFEED meant for cleaning/rinsing only, diesel will dilute the oil and you'll lose lubricity, not a good thing.
 

duncan

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I'm sure EZFEED meant for cleaning/rinsing only, diesel will dilute the oil and you'll lose lubricity, not a good thing.
Yeah thats why I asked. It's not the first strange thing I've read concerning dealing with military vehicles, so was wondering how he meant that.
 

duncan

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Heh, sure! Will take some friends along this weekend so they'll probably do some camera work too.

Today I revised the air blowoff valve, oil separator and what I think is the antifreeze for the air lines. Should get me some more air pressure now, but as I went for a test I ran out of diesel, heh. Dug up another 60litre drum from the workshop, refilled, but now there's air in the lines and pump. Will have to manually bleed the diesel lines tomorow, then retry. Steady progress though, can't wait for the next ride! People in the city are starting to notice something is going on now :twisted:
 

EZFEED

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Man please do Duncan! Hey, you ought to splice in an electric pump into your fuel line. My truck has one and it double couplings into the mechanical pump and this is factory, makes bleeding a breeze. I think all Tatra military engines have a manual bleeder pump as well. On mine its on the passenger side beside the fuel filter canister. On your V-8 I believe its on the drivers side just above the rearmost cylinder head. You should have a electric backup pump, I just dont beleive they wouldnt equip a 813 without one?????? Did you look under the truck in the frame rail or near it? There should be a unit with wires coming out of it with two lines and Banjo fittings running into one side of it. There will be a very small pull/push control on the dash or nearabouts that controls this.

I'm going to have to make a video myself soon too. I just drifted my Praga for the first time and by complete accident:-D Took it down a gravel road here and the road opened up to a large patch big enough to turn around in. Well I was going the wrong way and decided to try and turn around right there without stopping and in 4th gear.......I was doing like 70kmh though and just imagine the feeling of a 11.5 ton machine sliding arond in a circle dukes of hazard style...that was FUN!!!!:-D
 

duncan

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Olla, love your enthusiasm. I've had 2 busy weeks, so not much got done, sadly. I have located the fuel pump, its a tiiiiiiny hard to reach hand pump, driver side near the front most cylinder. Pumped that till my head ran red and my hands bleeding from scratching the surrounding parts, but still nothing. I've checked and theres plenty of diesel pressure on the lines (if I undo a banjo near the engine even slightly it comes gushing out), but she won't start.

What I did manage to do, replace the entire system of diesel lines, from tanks to engine and back, with nice stainless braided hoses, proper connectors everywhere and some nice shutoff valves at the tanks. Set me back quite a few, but she won't be leaking diesel anymore, so that'll pay itself back in time :wink:

Well, I'll got put some more handy work in, will bring my shabby camera with for today!
 

EZFEED

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Cool deal! Well I was wrong about the location of the hand pump I see LOL! But I did know it was at either end of the drivers side bank of cylinders! :lol:

Dude you should have an electric pump? Are you sure you dont have one?
 

duncan

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The newer T930-17 motors have the electric pump, because theyre multifuel and many light flammable fuels tend to vaporize after a bit. So there's an extra pump to aid the regular one, and to prime it.

I was struggling most of today to get the truck back to live. Cleaned the filters, checked the pump, etc. I'm ashamed to say it, but it took me a few hours to find out 2 of the fuel lines had crossed eachother when I ran them under the cab. So yeah, I was pumping fuel from the return line which obviously fails. That solved she ran almost instantly.
 
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EZFEED

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Good deal Duncan! You are really whipping the old girl back into shape!!!!:-D

Man I love those braided lines, you've got me thinking now! I wish you were closer, I'd indeed lend a helping hand!:-D
 

tatra813

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Good to see someone else actually using there tatra, I love hearing aobut your rides! just wait till you do some extremem offroading youll be amazed how it just keeps on going and going.

open the front hatch onthe engine in front of the truck and there is a manual fuel pump lever you can pump to prime the fuel line. I had a problem when I changed out one of my fuel tanks and then I could not reprime with the hand lever? I couldnt figure it out it always ran fine before. I ended up finding a pin hole in one of the fuel lines, it would suck air in but not leak fuel out, the only evidence of it was a eratic idle, but it was enough to not let me prime the line.

Where is the air reg located you are talking about. It the air blowoff valve ?oil seperater the one on the very back of the truck on the passanger side? it spits air every now and again? I was wandering what exactly that valve did, I was thinking it dumped air in the line when the pressure got too high, assuming the compressor pumps all the time. I should look at a diagram I guess to figure it out. Are you having any luck finding generic seals to rebuild them? or are you finding tatra rebuild kits?

For the power steering use automatic transmission fluid. If you look further back in the thread I had a bunch of the fluid questions answered you were asking about. If you cant figure it out let me know I have most of them writtendown.

By the way you may actually be in high range, the 1st gear in high range is still extremely low. I wasnt really happy with how fst and ease of shifting and the power of the truck until I really got the shifting down using the splitter correctly. Your drivers manual will tell you how. You dont have to double clutch except in first but I do it always anyway the splitter works a lot better that way.

Just wait till you get all 8 tires spinning in the dirt its a blast.

What kind of fittings are you getting to adapt the air lines to plastic? the only way I have found is to braze on a nipple on the existing fitting to do the conversion, which is easy but takes a lot longer.

Like I said before watch the oil level in your hubs, you dont want to run them dry it is a very difficult repair, hard to find parts and have to make special tools to get it all apart. Ive been putting lucas oil additive in them and it has even cut down on the hubs temps.

The only thing I really havnt used on my trucks are the winches, when I get time I need to see how well they work.. I also want to make a huge skid plate for the front of the truck to protect the engine, then I can start pushing dirt if necessary.

Damn I wish you were around here so we could go wheelin together.

I did have a problem with my air lines freezing this winter and I really wanted to go out in the snow, Ill have to figure a way to get around that next winter.

Keep us posted on your progress and I hope I can help out more with your questions.

Have a good one.

Dean
 

duncan

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Open the front hatch onthe engine in front of the truck and there is a manual fuel pump lever you can pump to prime the fuel line.
Yeah found that, and after I connected the lines properly (stupid me, stupid me, stupid me... :hammer:) it worked within seconds. It's all new lines made to fit to the original connectors on the tanks, fuel pump, injects, etc.

Where is the air reg located you are talking about. It the air blowoff valve ?oil seperater the one on the very back of the truck on the passanger side? it spits air every now and again? I was wandering what exactly that valve did, I was thinking it dumped air in the line when the pressure got too high, assuming the compressor pumps all the time. I should look at a diagram I guess to figure it out. Are you having any luck finding generic seals to rebuild them? or are you finding tatra rebuild kits?
The air regulator is the one on the passenger side all the way near the back. I forgot to take some pics for you, sorry. There's two units there, the first one is a bowl with a spring valve and a push knob on top. The lid screws off easy, well it should anyway, and there should be fluid in there.
From my understanding of the very limited details on the air system in my manual, it might be the Anti Freeze pump, which has to be filled with antifreeze. It does not specify any special fluid for it, so I will ask our local truck parts dealer. If I'm right, what it does is when you push the knob down it lets some antifreeze into the air system, which (obiously) prevents air lines freezing up to somewhere around -60 celcius, according to the manual.

The second one (the one most to the rear) is the pressure regulator and I think the oil separator too (not sure though). Theres a plastic pyramid shape cap on there. If you remove that it reveals a screw with a nut to secure it. You can undo the nut and turn the screw in and out to set the pressure at which it blows off. I left the engine running, screwed it in, and waited for the pressure to climb to little over 6 bar (manual states it should be set to 5.8 to 6 bar). Then ran to the back of the truck and unscrewed it untill it blew off. Now my air pressure is showing a nice 6 bar :-D Lock it with the nut and reseat the plastic cover, done!
There's a big bowl under the pressure regulator, which I thik is the oil separator. It has a plastic unit in that creates a few levels of "obstacles" for the air to pass through, and a piece of filter. It definately serves no purpose for the pressure, so thats why I assumed it to be the oil separator.

For the power steering use automatic transmission fluid. If you look further back in the thread I had a bunch of the fluid questions answered you were asking about. If you cant figure it out let me know I have most of them writtendown.
I was looking for those all over this thread but only found your question, not the answers. Will look again, and refill the streering with ATF.

By the way you may actually be in high range, the 1st gear in high range is still extremely low. I wasnt really happy with how fst and ease of shifting and the power of the truck until I really got the shifting down using the splitter correctly. Your drivers manual will tell you how. You dont have to double clutch except in first but I do it always anyway the splitter works a lot better that way.
My splitter has been professionally disconnected by the previous owner (read: they cut the wires). Have not fixed that yet. The 5 gears in low range got me through all terrain I've encountered so far, the 5 in high got me up to speed quite nicely. Expecially in high I notice I do need a working splitter, when you're working up the gears it's midly protesting.

For replacing the air lines I was thinking about using "hep2o" (Hep2O® The Flexible Push-fit Plastic Plumbing System From Wavin). That site only goes on about their range for plumbing though, can't find the professional stuff. It's used often for air pressure lines in workshops. It's a breeze to install since its all "cut to length, screw to fit" stuff. It should withstand well up to 12bar pressure, so all fine there.
Downsides are that the lines and connectors are quite big, and with all the fittings and stuff it'll get quite costly.

The other option is to get regular truck air lines and connectors, which sells for about $1.50 per metre. Main argument to use these is that theyre special made for trucks and trailers, not as expensive, and come colorized. The colorized bit is very interesting, I could use red for brakes, yellow for the tire inflation, blue for the solenoids, orange for the system to pressurize gearsbox and diffs, etc. Makes for easier problem tracking, which right now is a downright nightmare with something like 25 different rusty air lines running all over the place.

I'll go over my manual again to find how to check and refill the hub oil, and what oil to use. Assuming heavy gear oil, but will have to double check. I recall reading the amounts of oil used (0.5 litre for the front 4, 0.7 for the rear 4 wheels, I think), but I dont know where to drain and refill yet.

Time to get to the garage!
 

duncan

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Right, got the splitter to work. The clutch is still very dodgy though, so splitter doesnt behave too well. Shifting in general doesn't. Somehow the clutch doesn't disengage properly most of the time. Have to see what happens when I bleed it again, but need 2 people to do that since the truck is so big :)

Also I found the plugs for the hub oil. I know the amounts required, but I dont know how to top up and see how much I need to add. I seem te recall reading somewhere you have to put the wheels in a certain position and then fill up to the filler gap. Just cant remember where I read that. :roll:
 

duncan

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Found some more pics.

First one is the engine oil level dip stick (whoa thats a tiny one), it has only one indent on it, and the oil is precisely at that level. Would that be right, or is that the lower level and should I refill?

Next is the drivers side front compartment. Shows where I've put a small connector (the white thingy under the clutch fluid resevoir) to re-attach the splitter wires. Now the black box to the left of the big red power steering resevoir is leaking air on the connection with the pipe that connects to the bottom. It started doing that when I adjusted the pressure to from 4 to 6 bar, or maybe it's always been doing that and I just never noticed. Anyone knows what its for?
Also (barely) visible is the manual fuel pump. It's in the left compartment (left on the picture that is), right above the bowl with the red cap (which I'm pretty sure is where I refill engine oil).

Last up is a shot of my cleaned anti freeze (left) and aire pressure regulator (right). You can see the whire pyramid shaped plastic cap on the regulator that covers the regulator adjustment screw. The red cap on the regulator screws off and exposes a push knob that depressurizes the line (no clue why, might be the oil blow off or something).
On the left side the big red cap with the knob on top pumps a little bit of whatever fluid you put in that bottle into the air lines. My bottle was completely rusted through so I replaced it with a modified motorcycle oil filter housing :-D works a treat.
 
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