bill van snorkle Posted January 15, 2014 Share Posted January 15, 2014 Clutch M/cyl failed a couple of weeks ago, so I replaced it with a working one from a parts vehicle. It won't pump or transfer fluid to the pressure chamber. Replaced it with a new one that works perfectly well on the bench with a bleed screw fitted to the outlet. Again it doesn't pump or transfer fluid from reservoir to pressure chamber when fitted to vehicle. Can't generate any pressure to bleed the system. If I loosen bleed screw on slave cyl, fluid will dribble out, but still no action from the pedal. Removed M/cyl again and works on the bench ! Bloody infuriating. I am having to work outside in 43 degree temperatures and I am about to set fire to the frigging thing. Surely these things that are supposed to be serviceable and repairable in the bush shouldn't require pressure bleeding? Quote Link to comment Share on other sites More sharing options...
robertspark Posted January 15, 2014 Share Posted January 15, 2014 Sorry, I'll ask some daft questions, but they may prompt something with you looking at it in front of you... fresh set of eyes. ... when you pump it on the bench, do you get flow with resistance from the bleed screw (i.e bleed screw partially open)? ... if you close the bleed screw fully / wind it in.... will the pedal... or shaft still depress (if so, the seal must be letting by). ... [sorry I'll ask the obvious....] but when you put it back in, you are obviously putting the clevis pin / pin + circlip (I presume) back in between the clutch pedal and the master cylinder. .... it's hydraulics... if it's got fluid, and the master cylinder is conected to the pedal... and the seal is not letting by..... it will pump fluid through to the slave cylinder ..... you may have an air bubble in the master cylinder, but once you've let some fluid flow out the slave cylinder bleed screw under gravity, it will fill / flow into the pocket of the master cylinder... and you should then be able to clear the fluid .. it can't go anywhere else Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 15, 2014 Author Share Posted January 15, 2014 Sorry, I'll ask some daft questions, but they may prompt something with you looking at it in front of you... fresh set of eyes. ... when you pump it on the bench, do you get flow with resistance from the bleed screw (i.e bleed screw partially open)? ... if you close the bleed screw fully / wind it in.... will the pedal... or shaft still depress (if so, the seal must be letting by). ... [sorry I'll ask the obvious....] but when you put it back in, you are obviously putting the clevis pin / pin + circlip (I presume) back in between the clutch pedal and the master cylinder. .... it's hydraulics... if it's got fluid, and the master cylinder is conected to the pedal... and the seal is not letting by..... it will pump fluid through to the slave cylinder ..... you may have an air bubble in the master cylinder, but once you've let some fluid flow out the slave cylinder bleed screw under gravity, it will fill / flow into the pocket of the master cylinder... and you should then be able to clear the fluid .. it can't go anywhere else Robert. After bleeding the M/cyl on the bench, I fit it up to the vehicle with the bleed screw still fitted, and when I connect up the pedal it is solid and doesn't bypass. It's when I remove the bleed screw and connect the pipe to the slave, that is when fluid doesn't enter the pressure chamber. It just doesn't make any sense, and seems to require a one way valve at the M/cyl outlet for bleeding purposes.Unfortunately I can't get at the flexible hose to clamp it to replicate a one way valve. I've parked the vehicle left hand down, right hand down, and on compound angles when attempting to bleed, all to no avail. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 16, 2014 Share Posted January 16, 2014 Could it be a dodgy hose/brakeline? These can do the weirdest things to you, working as a shutter valve when you put pressure to it or just house an enormous amount of air bobbles, effectively blocking the fluid. The way I usually bench test mastercylinders in general is putting a finger on the exit port and activate the piston with the other hand, if you can't hold the fluid in with the pressure of your finger its generally ok. But seems you have concluded that part. Quote Link to comment Share on other sites More sharing options...
Daan Posted January 16, 2014 Share Posted January 16, 2014 I normally take out the master, slave and hose and bleed them as an assembly on the bench. For some reason trying to bleed it in situ just never works. I havent worked out why, but that is the way for me. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 16, 2014 Author Share Posted January 16, 2014 I normally take out the master, slave and hose and bleed them as an assembly on the bench. For some reason trying to bleed it in situ just never works. I havent worked out why, but that is the way for me. To do that on the RRC would still require that the pipe and hose be disconnected from the slave cylinder in order to be able to refit them to the vehicle. I'm tempted to nick a M/cyl off a 60 series Landcruiser parts vehicle in the paddock and adapt that. I think you were right Daan when you commented once that " life is too short to waste most of it maintaining any more than one Landrover product." Or words to that effect. Quote Link to comment Share on other sites More sharing options...
steve_a Posted January 16, 2014 Share Posted January 16, 2014 One of the pedals on these cars is fitted with a elliptic pin to the pedal, I can't remember what one, and I might even be making it up, but the pin may be the wrong way round and you aren't getting throw. If you can push fluid out though then it's not throw. In that case bleed out the slave, I have found that pressure bleeding, in the UK you had gunsons easy bleed/easy discharge of all fluid, I haven't seen them here, but the SCA one way valves actually work pretty well. The only other thing I found was doing it in a kind short pump x3 quick, long run all the way down, type action. And come on Bill, 43c? It was 46.1c here today, you guys have it easy down in Vic :-p Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 16, 2014 Author Share Posted January 16, 2014 46.1 degrees Steve ? But you weren't phaffing about out there working on an un co operative Range Rover.! Yes the clutch has the elliptical pin, but no matter what position it is turned makes no difference. Almost as annoying is that the master cylinder was sold to me as a direct replacement for the no longer available Girlock unit, but I had to knock a dent in the bulkhead in order to remove the lid from the fluid reservoir. the firm I bought it from are still away on Xmas holidays.In Adelaide as it happens. Quote Link to comment Share on other sites More sharing options...
Diff Posted January 16, 2014 Share Posted January 16, 2014 Clutch M/cyl failed a couple of weeks ago, so I replaced it with a working one from a parts vehicle. It won't pump or transfer fluid to the pressure chamber. Replaced it with a new one that works perfectly well on the bench with a bleed screw fitted to the outlet. Again it doesn't pump or transfer fluid from reservoir to pressure chamber when fitted to vehicle. Can't generate any pressure to bleed the system. If I loosen bleed screw on slave cyl, fluid will dribble out, but still no action from the pedal. Removed M/cyl again and works on the bench ! Bloody infuriating. I am having to work outside in 43 degree temperatures and I am about to set fire to the frigging thing. Surely these things that are supposed to be serviceable and repairable in the bush shouldn't require pressure bleeding? If there is no free play at the pedal it will cause this problem, so presumably there is something causing the pushrod to be pushed into the cylinder slightly once mounted. perhaps the replacement master cylinders are slightly differently dimensioned, or the pushrods are slightly longer than the original? Regards, Diff Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 17, 2014 Author Share Posted January 17, 2014 If there is no free play at the pedal it will cause this problem, so presumably there is something causing the pushrod to be pushed into the cylinder slightly once mounted. perhaps the replacement master cylinders are slightly differently dimensioned, or the pushrods are slightly longer than the original? Regards, Diff The eccentric pushrod bush allows for sufficient freeplay adjustment, I parked the vehicle on a left side down 30 degree sideslope over night, and this morning there is a very slight improvement in pedal feel, but nowhere near good enough. I'll come back to it once this heatwave passes in a day or two . Lucky that it is just a spare vehicle and I don't depend on it. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted January 17, 2014 Share Posted January 17, 2014 I'm guessing you have an air leak downstream, maybe in the slave. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 17, 2014 Author Share Posted January 17, 2014 I'm guessing you have an air leak downstream, maybe in the slave. Removed the slave cyl the other day. was in good order but gave bore a light hone and fitted a new rubber anyway. Quote Link to comment Share on other sites More sharing options...
redneck Posted January 17, 2014 Share Posted January 17, 2014 Having had this problem on a few vehicles, I believe what happens is the seal in the master cylinder doesn't move far enough back, therefore not allowing any new fuid in from the reservoir. In normal use the the clutch pushes the seal back far enough via the slave cylinder. best method for bleeding that I've found is to reverse bleed the system, I use a garden sprayer to do it. Quote Link to comment Share on other sites More sharing options...
robertspark Posted January 17, 2014 Share Posted January 17, 2014 Just a thought or suggestion..... on the LR90, the clutch master cylinder feed connection comes off the top of the reservoir... it then runs across the bulkhead from memory, and drops down the passengers side (RHD) to the clutch slave cylinder (on a RV8 anyway from memory, mine has been in bits some time). I suspect that this loop upwards from the master cylinder is trapping air in the up and over loop, and it's not being forced out by the level of the clutch fluid in the reservoir.... (static head). If you're a bit of a smart ar*e... you could try pressure backfeeding the clutch line via the save cylinder.... Length of hose onto the slave cylinder bleed screw (partially open!).... maybe a plastic coke bottle, milk bottle or something (clean), with the hose draped in the bottom with 2 holes in the lid, and a second hose from the lid to an air supply (spare tyre / compressor / foot pump....) Basically imitating the Gunsons (or other) clutch and break bleeder.... picture below (but this one feeds it from the master cylinder cap... of you have a space cap you could put an airline on that too and force what's in the reservoir through): Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 17, 2014 Author Share Posted January 17, 2014 Thanks for all the suggestions. I finally had some success by leaving the vehicle on the sideslope, where it would seem that fluid gradually trickled down to the slave cylinder and allowing air to come back up into the master cyl. Occasionally during the day I propped the pedal in the down position with a stick for an hour or so in the hope that a little pressure would force the air to the top a little quicker. Anyway this morning I have a fully operation clutch, and I haven't touched the bleed screw yet. Not sure I am game to either. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 30, 2014 Author Share Posted January 30, 2014 The clutch hydraulics failed again a couple of weeks ago, so I parked it up in frustration and moved on to other more important matters. I had a bit of free time today and despite no fluid leaks I decided to completely expose the pipe from the m/cylinder to the hydraulic hose. It was buried under wiring and Aircon hoses held to the bulkhead with retaining clips and virtually inaccessible self tapping screws. Anyway, got to it eventually and spotted a section where the aircon hose had rubbed almost but not quite through the hydraulic pipe. On closer inspection with a magnifying glass I noticed the tiniest dot that I suspected was a pin hole with the thinnest membrane of metal blocking it in only one direction that acted as a one way valve, allowing air to leak into the system but not allowing any external fluid leakage. I put a dob of 5 minute epoxy resin over the hole and now the clutch works fine. Landrover ownership is never boring, but frequently infuriating. Quote Link to comment Share on other sites More sharing options...
missingsid Posted January 30, 2014 Share Posted January 30, 2014 Bill, It's never something normal with you allways something special!! Glad you got to the bottom of it. Marc Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 30, 2014 Share Posted January 30, 2014 Glad you found it Bill. Quote Link to comment Share on other sites More sharing options...
Nigelw Posted January 30, 2014 Share Posted January 30, 2014 My god what a palava!!! good to know you are back up and running in her. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted January 30, 2014 Author Share Posted January 30, 2014 Yes, thanks all, I'm glad that my threatening the Rangey with a can of petrol and box of matches persuaded it to co-operate this time. Quote Link to comment Share on other sites More sharing options...
Boydie Posted February 2, 2014 Share Posted February 2, 2014 Try this method of bleeding, it's one I have used for years without any hassles. Get a good quality transmission oil pump, one that will hold at least 1/2 a litre (mine holds a litre) fit a good quality pressure hose on it secured at the pump by preferably a clamp ring or a hose clamp, I have high pressure fuel line on mine -3/8". Once you have filled the pump with hydraulic fluid and holding it vertically to expell any air in the pump and hose fit the hose to the bleed nipple of the clutch or brake cylinder and loosen it a couple of turns. Loosen the fluid line union at the master cylinder and pump fluid back up to the master cylinder from the slave. Air will want to rise to the highest point and while messy and uses more hydraulic fluid thhan the conventional method this system has always worked for me and negates the need to have a second person pump the peddle while you are bleeding below. It takes me less than an hour to fully replace all the brake fluid on my Disco using this method starting from the furthest to the closest brake, I've also used the same pump to bleed clutches and it works and its simple. Quote Link to comment Share on other sites More sharing options...
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