sirhc Posted June 20, 2010 Share Posted June 20, 2010 I have a problem with the brakes on my Lightweight. Nothing I do seems to help. When you press the pedal nothing happens, the pedal goes straight to the floor. On the second press the brakes apply the vehicle stops. So far I have: - Checked adjustment - Fitted new wheel cylinders - Fitted new brake shoes - Fitted new hoses - Fitted a new master cylinder - Stripped and checked the shuttle valve I am bleeding it with the easy bleed and there is no air in the system. I can not find any leaks. What should I try next?! Chris Quote Link to comment Share on other sites More sharing options...
ruxy Posted June 20, 2010 Share Posted June 20, 2010 What is the truck VRM ? Is the master cylinder a genuine Lucas Girling (TRW) ? Any ID on the master cylinder box it was supplied in ? Have you changed any pipework at the master cylinder ? Quote Link to comment Share on other sites More sharing options...
antarmike Posted June 20, 2010 Share Posted June 20, 2010 I have a problem with the brakes on my Lightweight. Nothing I do seems to help. When you press the pedal nothing happens, the pedal goes straight to the floor. On the second press the brakes apply the vehicle stops. So far I have: - Checked adjustment - Fitted new wheel cylinders - Fitted new brake shoes - Fitted new hoses - Fitted a new master cylinder - Stripped and checked the shuttle valve I am bleeding it with the easy bleed and there is no air in the system. I can not find any leaks. What should I try next?! Chris When you have pumped the pedal and the brakes are on, does the pedal feeel rock solid, or if you keep the preesure on, does the pedal slowly creep down to the floor? Are you losing any fluid? is the level in the reservoir staying the same. Are the brake cylinders matched to the master cylinder. Land rover master cylinders and brake cylinders dome in different diameters. If you have a small bore master, and large bore wheel cylinders, it might not be shifting enough fluid to put the brakes on, in one pedal pump. I suspect there is too much clearance between the shoes and the drums, Have you re-checked all the adjusters and got the shoes as close to the drums as possible? Are you bleding furthest wheel cylinder first and nearest cylinder last? Is the rod length correct between pedal and master cylinder piston to the book dimension? Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted June 20, 2010 Share Posted June 20, 2010 Try adjusting the shoes tight to the drums and then bleed, readjust afterwards. Another problem on bleeding is the shuttle valve moving across, we used to remove the switch and repalce with a specially made locking screw, whilst bleeding, refitting the switch afterwards. Quote Link to comment Share on other sites More sharing options...
sirhc Posted June 20, 2010 Author Share Posted June 20, 2010 Ok, from the top... - The tuck is 20HF93. - I did have a genuine master cylinder, I fitted a genuine kit and it made no difference. I have stuck a new Britpart one on and get the same problem. - All cylinders are correct for the vehicle. - I have not changed any pipework at the master cylinder, but the hoses and pipes to the wheel cylinders are new. - I am not losing any fluid. - The adjusters are correct. - I am bleeding in the correct order. - When I pump the pedal it keeps the pressure. With the old master cylinder it did slowly go down further. - As for rod length, I've not messed with it and so I assume it's correct. My current thoughts are.. either the shuttle valve is playing up, or the new Britpart parts are junk and do not work out of the box. I can't see any adjustment at the pedal end, but maybe a bit more travel would help. When I bought the vehicle the brakes were perfect. Whilst going to Withams one day I had a leak on the back cylinder, warning light came on. I fitted new rear cylinders, bled and then it was fine. My current problems started after damaging one pipe while fitting the parabolic springs a few years ago. I replaced the pipe with a new one, bled the brakes and they were ok, passed the MOT but never felt quite right. Since then they have got slowly worse. With Beltring approaching I started replacing bits to try and get it sorted, but now it's doing my head in! Thanks for the replies so far, any other thoughts? Chris Quote Link to comment Share on other sites More sharing options...
ferrettkitt Posted June 20, 2010 Share Posted June 20, 2010 Does it have a servo? I'm presuming not as its the only thing that you haven't mentioned Quote Link to comment Share on other sites More sharing options...
Tony B Posted June 20, 2010 Share Posted June 20, 2010 You don't mention flexi hoses and have the shoes been set up properly? First thought is shoe adjustment. Quote Link to comment Share on other sites More sharing options...
ruxy Posted June 20, 2010 Share Posted June 20, 2010 Shuttle valves are normally not a problem (they don't do much) - the overhaul kit for yours is Rover No. AAU1714 , would have been best if you had at least re-sealed. Does the brake test illuminate as early warning you have moved the spool ? If you do just release the other end pressure and tap the pedal until centralized (bleeding by foot - pump very slow) You should have master cylinder 569671 (with 10" dia. drums front & rear) , I was just wondering if you had managed to couple up a early S3 109" No. 90577520 MC. You should have 1.1/4" bore front & 1" bore rear slave cyls. ---------------- Worth checking pedal height & wear in pedal box, but would have to be well out to do this. With new linings , even on worn drums - you should easy get a firm pedal. With the pedal going straight through - I still think it is a master cylinder problem. Normally with 10" and the so called dreaded front 11" - I bleed with a assistant on the pedal but sometimes use a Gunsons Easybleed. Normally if you are taking air in somewhere - then a pressure test with your full weight on the pedal will show a fluid leak there. I think I would be getting a new genuine master cylinder. Quote Link to comment Share on other sites More sharing options...
sirhc Posted June 20, 2010 Author Share Posted June 20, 2010 The master cylinder I have fitted is 569671. I have 243296 /7 front wheel cylinders, which are 1 1/4" so I think all is well there. The brake test button has never done anything since I have had the vehicle, although I am sure the shuttle valve works as the light has come on in the past when there has been a leaky cylinder. Bleeding with the easy bleed, or conventionally with someone else pumping the pedal both produce the same results... no traces of any air anywhere. I think I'll look up the price for a genuine master cylinder, and maybe an overhaul kit for the shuttle valve and servo while I am at it. I've never had so much grief with brakes before, even on the Fox when they caught fire due to a dodgy servo! Chris Quote Link to comment Share on other sites More sharing options...
sirhc Posted June 20, 2010 Author Share Posted June 20, 2010 You don't mention flexi hoses and have the shoes been set up properly? First thought is shoe adjustment. I think you'll find I did mention the hoses... see my original post! Quote Link to comment Share on other sites More sharing options...
Tony B Posted June 20, 2010 Share Posted June 20, 2010 I think you'll find I did mention the hoses... see my original post! Sorry mate long day. Try using the Gunson to put gentle pressure on the resovoir, then manual pump the peadle. That may help. Quote Link to comment Share on other sites More sharing options...
mike65 Posted June 20, 2010 Share Posted June 20, 2010 Had a soft pedal when I replaced shoes, a couple of wheel cylinders and master on my 109 earlier this year. Would go almost all the way to the floor on first press, when pumped again (quickly) the wheels locked solid. Did all the bleeding stuff several times to no real effect. Only seemed to get better when we had adjusted, tested, readjusted more times than I care to count. Drone my assistant (father) mad. Normally I get annoyed first. Have you tried adjusting the brakes fully on and checking to see if that gives you a firm pedal once pistons fully out? May not be conventional but if system is full of fluid and they cannot move out you should have a olid pedal. Had the seal between the dual circuits fail on a car once, foot goes to the floor and you neeed to pump really hard to get brakes. Woud not expect on a new master but I suspect it can happen. Mike Quote Link to comment Share on other sites More sharing options...
sirhc Posted June 20, 2010 Author Share Posted June 20, 2010 Had a soft pedal when I replaced shoes, a couple of wheel cylinders and master on my 109 earlier this year.Would go almost all the way to the floor on first press, when pumped again (quickly) the wheels locked solid. Did all the bleeding stuff several times to no real effect. Only seemed to get better when we had adjusted, tested, readjusted more times than I care to count. Drone my assistant (father) mad. Normally I get annoyed first. Mike, This does sound like my problem. I will have to have another go at adjusting it. Still deciding if I want to buy another new master cylinder at the moment...! Chris Quote Link to comment Share on other sites More sharing options...
Mk3iain Posted June 20, 2010 Share Posted June 20, 2010 This rings a bell from way back. I sold my lightweight on about 14 years ago or so and I remember just this problem. I think the advice at the time was that they can be a bitch to bleed! so not necessarily any component at fault. I think I just persisted at bleeding untill it was right, using the technique from the book! Wish I could be of more help. Iain Quote Link to comment Share on other sites More sharing options...
Chrisg Posted June 20, 2010 Share Posted June 20, 2010 Have you tried clamping all the flex hoses then see if the pedal goes straight down to the floor and releasing one at a time trying the brakes in between ? Quote Link to comment Share on other sites More sharing options...
airportable Posted June 20, 2010 Share Posted June 20, 2010 This rings a bell from way back.I sold my lightweight on about 14 years ago or so and I remember just this problem. I think the advice at the time was that they can be a bitch to bleed! so not necessarily any component at fault. I think I just persisted at bleeding untill it was right, using the technique from the book! Wish I could be of more help. Iain Funny enough this sounds like the problem I had a few years ago. I never fit any brake part other than I think mine are Girling? Had real problem bleeding, Local garage (used to Landies) told me to attatch tube to bleed nipple and leave other end in jar of fluid and let it slowly drain through, after a few min. before tightening nipple one only slow push on pedel and tighten before bottom. I remember this system worked for me. My mate with His bleed kits etc. had no luck at all.Just a thought. Andy. Quote Link to comment Share on other sites More sharing options...
jcbpete Posted June 20, 2010 Share Posted June 20, 2010 had same fault with early 109 try deadjusting all drums clamp all shoes with g clamps. so cylinders are all closed so no air can be trapped. then pressure bleed. Quote Link to comment Share on other sites More sharing options...
Bluebell Posted June 20, 2010 Share Posted June 20, 2010 Hi. I havent read the whole thread, but here are some basics. If your pedal is spongy, it has air in it.(the system) If you can pump it up, and the pedal goes hard, its NOT air, its adjustment. Dont complicate it. If you had a firm pedal, that slowly required more travel ie you had to push the pedal a second time. Then its adjustment. Either there is something wrong with your adjusters,or what you are doing with them. if not that, then are the pistons staying in contact with the shoes? If they are not, then you may have a line pressure valve in the master cylinder, that is not holding. I dont know your system. These are general comments. You need to work through these possibilities. Do like Richard said. Block your Landy up, then lock up each adjuster, making sure each one is stopping the wheel turning.(by backing off the other one in each brake) When you have all (8?) shoes locked by (8?) adjusters. then how much travel do you have at the pedal? Get back to me. Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted June 20, 2010 Share Posted June 20, 2010 Sounds to me like air in the system. If you first brake and it goes to the floor there is obviously no resistance in the cylinder, then when you pump again it's OK meaning you then have pressure. I know you have said you have bled the system and no air is in it, but I've had a similar thing happen to me in the past. Quote Link to comment Share on other sites More sharing options...
julezee001 Posted June 20, 2010 Share Posted June 20, 2010 Have you tried clamping all the flex hoses then see if the pedal goes straight down to the floor and releasing one at a time trying the brakes in between ? I'd go with this method as a quick way to diagnose where the problem is. Jules Quote Link to comment Share on other sites More sharing options...
andrewroberts.1953 Posted June 21, 2010 Share Posted June 21, 2010 Get a bike inner tube, cut it in half. Tie one end off, and put the other end over the top of the fluid res. put a enought pressure in the inner tube to make the tube just begine to ballon. Bleed brakes again, making sure you keep some pressure in the tube. The problem is that the master cylinder is not able to pump fluid, due to the design of the seals etc in the cylinder not being wet. The other way, is lift the front onf the rover till it's at about 30 degrees. I have had to do this lots of times with rovers. Quote Link to comment Share on other sites More sharing options...
ruxy Posted June 21, 2010 Share Posted June 21, 2010 Have you tried clamping all the flex hoses then see if the pedal goes straight down to the floor and releasing one at a time trying the brakes in between ? Even with pukka hose clamps - you will damage many modern hoses as they have a built up construction cover sheath, braided ply and a nylon tube fluid liner (that you will crush damage). Have you measured the drum dia. (in theory you have very little permissible wear). There are many makes of cheap shoes that are illfitting - even in a new brake drum. Frankly - there are new rubbish drums and shoes being sold as well as hydraulics. It could be that you need more fluid displacement that than the master cylinder can supply on a single stroke ? Because of this , at this stage - I would put a small G clamp on each brake slave cylinder to reduce the volume to minimum (rather than hard adjust the shoes outwards on to worn drum surface). If you still can't get a solid pedal on the first stroke - then it is the master cylinder. Quote Link to comment Share on other sites More sharing options...
Chrisg Posted June 23, 2010 Share Posted June 23, 2010 Any luck with the brakes yet Chris? Quote Link to comment Share on other sites More sharing options...
sirhc Posted June 23, 2010 Author Share Posted June 23, 2010 Any luck with the brakes yet Chris? Not yet Chris, will try again on Sunday! Chris Quote Link to comment Share on other sites More sharing options...
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