Hydrostatic transmission

guys you remember the 750. i started on a long time ago about like all my other projects yeah i get so many of these time-consuming projects you know the stories just i just get to them when i can i got everybody's on my ass i've been working on that i i know i'll catch grief about it about the fuel truck that we did the carb conversion i've almost got it ready to start uh those guys have been super patient with me they they know i'm busier than hell and everything's coming at me at one time and they're in the same way they're the same boat i mean everybody that works for a living right now is is behind because you can't get any help you can't get parts it's just you just do what you can that's all you can do that being said on this old girl here we got the control valve completely rebuilt and it helps it a whole lot it has way better control the owner was right here with me he goes it's getting around a lot better he said but what happens is so what we did this is old places are clean he's cleaning this place up here so what i did it was turning and counter rotating a lot better than it was but it just still didn't have the power so i put my blade up against that pile of there and just put her full forward and what is happening the left track spins on the right track we got a problem with we got a problem with that right track and i'll tell you another way that you can tell with our right hydrostatic if you read this steering system check with the engine at slow idle move forward neutral reverse about one inch and two forward and observe charge pressure while steering to the stop and counter rotate position for left and right track if charge pressure drops excessively transmission being powered may have excessive leakage if see chain if charge pressure drops excessively transmission being powered may have excessive leakage if tractors do not stop and kind of rotate so yeah so i'll show you i'll show you so we know that the left track will sit there and spin and dig a hole well you can kind of see where the left track was i don't know if it can not you can kind of tell where the left track was yeah see it was if i really hogged into it the left track could start spinning the right track never would never would do anything but you hit the right pedal and the charge pressure goes down hopefully my worms see it actually when the oil is cold it doesn't it acts pretty pretty good as soon as that oil warms up that's when she falls on her face let's just test her out real quick see if it still does the same thing that i was seeing before there's our charge pressure for it off okay which is fine because there's an operating charge relief and a neutral charge relief so i'm going to hit the left brake pedal watch when i hit the right brake pedal see how it changes when i use the right brake pedal came up actually [Applause] so [Applause] so it's not doing the same thing that it was before it's actually going up in pressure when you hit the right brake pedal now before it was going down now it's changed i wonder if i'll go drive it though let's look at the i'm going to look at the theory of operation before i so it tells you the track that's being powered does that mean it's being powered when you're hitting the right pedal the right one's being powered not sure let me read theory of operation here okay here's the here's their little chart action transmission uh transmission oil operating temperature automatic control valve handle shut off handle down engine fast idle operating unit under load stall load to stall tracks question does charge pressure on gauge drop excessively yes it does go over here action for neutral reverse control handle forward operate unit under load push down steering pedals one at a time watch charge pressure the pedal that causes charge pressure to rise indicates problem transmission well you guys saw the pressure rise and well a minute ago it was dropping so then we're going to run that little test just real quick action remove load move forward neutral reverse control handle through full range is charge pressure related to phasing or direction let's do this test right here we'll put her back up against that bank and see what it does and watch our pedals okay [Music] so uh [Music] my camera so so so so [Music] i'm almost certain it's in the right side so let's look at the book a little more uh yeah the pressure goes up when you hit the right pedal let's do a little more reading here so so we know that four neutral can go forward operate until check the pedal that causes charge pressure to rise indicates problem transmission okay action move load is charge pressure loss related to phasing or direction i think it's more to me it seems like it's more related to phasing once you get a little motor speed out of it so i i i think i think phasing okay phasing check operating charge relief valve i already did that motor servo cylinder o-ring and pump valve and bearing plate separation check bypass valve let's see so no would be over here i got to make sure that i'm getting this phasing thing figured out it's not directional okay so it's not directional because it does exactly the same thing and it does exactly the same thing in for or reverse it's not directional it's it's when the motor is being phased because if if if the charge pressure didn't leak down and forward but it didn't reverse then you know it would be directional so it's in the phasing circuit of it and we've already had the operating charge relief valve out of this thing and it's they're fine so the the thing next to be motor servo cylinder o-ring and pump valve and bearing plate separation which is more than likely what it is so let's see what we got to do to check about that so so [Music] got a hell of a nest in there for boss we got to kill those bastards yeah we're gonna have a problem here look at them right in there here we go [Music] now that'll get them good and pissed off [Music] yeah yeah they're mad they are pissed off now i thought i got both of them so [Music] [Music] uh so [Music] so kind of tighten that valve up on that shut off it's leaking is that better okay a little wasp here let's see give him a little shot there you go i give him a little shot there nice okay here's our here's what we're trying to access now we're gonna move this plate get that out of the way and then the battery tray will come out of it uh i think the battery tray yeah i gotta take one more bolt loose on the battery tray and then i can remove this plate all right i'm gonna cheat i'm going to cheat [Music] let's see i need to go that way i got the sump grain 25 gallons of oil [Music] i sure thought it was [Music] should be loose now okay let's go ahead and take this little clear off see if i can swing it over out of the way and cat plug kit and cap these i don't have a uh this line is going to be full oral the tank's empty though but the hose will be full of oil it's not anymore though okay let me get some plugs and caps so this is gonna have to come out of here can't get past this i gotta pull all this out all right let's get our own swung out here damn it high pressure wash and pressure washed and pressure washed and i still didn't get all the crap out of it he was is built up in there like wouldn't believe man so this so far here looks pretty good i gotta get some four sleep typical hydrostat job there's oil everywhere anyway on this on this swat this is your squash plate right here pretty good size squash plate but see here i don't know if the camera is picking that up or not let me get my phone see the servo pistons all scratched up real bad that's that's causing a lot of our problems right there so that's causing a lot of our charge pressure loss across that servo piston the rotating group looked really good in it this would be the rotating group here's the piston block where the pistons go in here's the pistons those all look pretty damn good you just got to be really careful on those there's a bearing plate here you got to make sure you don't scratch you don't want to scratch this or scratch that bearing plate you got to be really careful when you're pulling them apart but we need a servo piston and a servo cylinder right now but tomorrow morning i'm going to get up early and i'm going to tear this pump apart so that'll be tomorrow morning i'm whipped for the day and uh tomorrow's another day but i think we're on the road to success now we've definitely found a major contributor to our charge pressure problem anyhow thanks for watching i'll probably video tearing that pump apart in the morning making a separate video about that

Channel: western truck and tractor repair

Views: 59,249

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Id: HniXp-A6rWE

Length: 29min 54sec (1794 seconds)

Published: Thu Aug 05 2021