SH4RKY Posted September 3, 2011 Share Posted September 3, 2011 Military 90. 1986. As far as I know, its the original rear axel and brakes etc. The problem I have is that the Drivers side Rear wheel locks under braking. Under hard braking the passenger side will actually drag the drivers side round as the rear drivers looses traction. It will skid under moderate braking. Following the various guides, workshop manual and info in this thread: http://forums.lr4x4.com/index.php?showtopic=60307&st=20&gopid=592479entry592479 I have taken the hub off to look for problems. Everything looks ok. No oil, shoes look fine, no odd wear patterns, hub is clean, cylinder is moving etc etc. The only thing that seems to be different is that the retaining ring at the bottom is on the rear shoe rather than the front and im a little confused as to my spring locations. Does this look right? Front view of rear brake: Front top sping, attached to the adjuster on the back of the hub: Front bottom spring and retaining ring: Rear view of the rear brake: Rear view of the top spring. Is this the problem? The spring isn’t attached to the rear shoe at the top, its attached to the back of the hub. Shouldn’t the shoes be attached by springs top and bottom to pull them together?? Rear view of the bottom spring: Help! I need to check the other side, but with a limit on jacks etc I can only do one side at a time so want to make sure this side is ok before reassembling! Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted September 3, 2011 Author Share Posted September 3, 2011 After looking at the evidence, i dont think a spring is required at the top. the ones that have the springs are the 110s. Not sure about that bottom retaining plate though. it holds the rear shoe in place, without it the shoe would come out. the manual clearly shows it but unfortunately it doesnt say which side the image is! haha Going to have a look at the other side, as its been suggested that the opposite side to the problem can lock. Quote Link to comment Share on other sites More sharing options...
western Posted September 3, 2011 Share Posted September 3, 2011 workshop book shows long finger of top spring on backplate post & short finger on brake shoe, bottom spring on brake shoes, see Section 70, page 8 Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted September 3, 2011 Author Share Posted September 3, 2011 workshop book shows long finger of top spring on backplate post & short finger on brake shoe, bottom spring on brake shoes, see Section 70, page 8 Yeah, that was the image that was confusing me. all the photos suggested mine are fine, but that image is a little hard to figure out! Other side was much the same. the bottom spring is stretched and much looser, so that will need replacing. Less wear on the shoes though. cleaned and reassembled everything, adjusted the brakes with the same amount of adjustment and the wheel still locks up. hmph... the cylinders looked a little different, so perhaps a touch more adjusting will slacken off the locking wheel? Had a quick look on paddocks and couldnt see replacment springs, are these freely available or part of a kit or something?? Wondering if the fronts are lacking in some regard... Ill have to check. Quote Link to comment Share on other sites More sharing options...
western Posted September 3, 2011 Share Posted September 3, 2011 90 drum brake part numbers are on page 598 Quote Link to comment Share on other sites More sharing options...
Ian Barrett Posted September 3, 2011 Share Posted September 3, 2011 I have an '87 Ninety and have just done the rear brakes. The springs should be attached top and bottom to both shoes, not the backplate. So your top spring doesn't look right. the spring should have a short end, spring, long end. The long end should be attached to the post on the back of the shoe next to the adjuster cam (snail shape thing) making sure the long bit of the spring is tucked behind the cam. Then pull the other shoe forward slightly so you can see down the back of it and with something suitable pull the short end of the spring onto the post on the back of the shoe. It will be hard to pull this on and watch your fingers. I couldn't figure out what possible use the bottom banjo shaped retainer could be, and both shoes are threaded the same. From memory I think I put the retainer on the rear facing shoes. Did you clean the peg the shoes sit on/in at the bottom? Give it a good clean inside the groove the shoes sit in (a thin strip of emery does it nicely) and copper slip it. Hope that helps and good luck. Quote Link to comment Share on other sites More sharing options...
zeerover Posted September 4, 2011 Share Posted September 4, 2011 "I have an '87 Ninety and have just done the rear brakes. The springs should be attached top and bottom to both shoes, not the backplate. So your top spring doesn't look right." Your wrong, the pictures showing the correct set up! Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted September 4, 2011 Share Posted September 4, 2011 Indeed, the bottom spring goes on both shoes. The top spring goes on the front (ie. the leading) shoe only, and then onto the peg on the backplate. I'd replace the springs if you're having problems with the brakes locking up. Check the cylinders slide in/out freely too. Quote Link to comment Share on other sites More sharing options...
Ian Barrett Posted September 4, 2011 Share Posted September 4, 2011 oh my god. I've just checked my photos and you are right, I'm talking out of my arse. The top spring does attach to the front leading shoe only and the backplate at the rear, so your photos do indeed look like you have it all correct. My apologies and I'll go flush my head down the toilet now Quote Link to comment Share on other sites More sharing options...
landrover620 Posted September 4, 2011 Share Posted September 4, 2011 I bought new springs from paddocks for my 90 last year they were only a few quid. Your springs are in the correct places, someone had put my top spring on both shoes and my brakes used to jam on when cold at times, new springs and correct set up problem solved. Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted September 5, 2011 Author Share Posted September 5, 2011 Thanks for the replies. Ill probably replace the shoes and springs, maybe the drums and either reseal the pistons or buy new cylinders. Parts seem cheap enough so no harm in refreshing the brakes, considering how important they are! Measured the drum, they are 10". I'll check the fronts out too, make sure all the pistons are working. Again, might just clean, reseal and replace pads considering the fairly low cost of parts... Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted September 5, 2011 Share Posted September 5, 2011 Depends on what your vehicle is used for, but if you go off-road at all then it might be worth considering bunging a Disco axle under there. £100 would buy you a decent one and then you could forget about adjusting drums and having 'interesting' braking after wading/mud. If the vehicle is mainly used on the road it's probably not worth it, unless you fancy the upgrade of course, since once they're properly set up the drums should work fine Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted September 5, 2011 Author Share Posted September 5, 2011 Hmm... Does an axle swap require adjusting anything else in the braking system?? as in bias front to back or the vacuum thingy up front?? If the axle comes with the brakes attached for that much, then yeah it wouldnt be much more than just renewing drums! Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted September 5, 2011 Share Posted September 5, 2011 Didn't on mine. Disco axles bolt straight underneath (make sure the prop flange matches, as some Discos used a different flange), and the brakes just hook up. I didn't adjust any bias valves or anything. The difference in braking performance isn't that great, after all the back brakes do bugger all most of the time anyway, but the difference in pedal travel/feel and the fact that the brakes don't stop working when muddy/wet is the main reason for the change. Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted September 6, 2011 Author Share Posted September 6, 2011 carp, one of the hubs is pissing out oil now. Any my heater has decided not to work... Just when I thought it was beginning to behave itself Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted September 10, 2011 Author Share Posted September 10, 2011 Refurbed the brakes today. Removed old shoes and springs, general clean and tidy up. Checked that the pistons were moving freely. Fitted new mintex shoes and replacement springs. Disassembled the leaking hub and rebuilt using a new outer seal and replaced the gasket which had all but disintegrated. Hub cap was new so checked for defects and reused. Before After These were the springs from the side that was not locking up. No pressure was being applied by the bottom spring, so likely the brake was not braking efficiently: So anyway; under heavy braking, as in emergency stop style, both rears will lock!! At least they are consistent now, haha. Checked the fronts to make sure they are ok, discs are practically new. loads of life on pads. no sign of sticking calipers. So fairly confident the fronts are working as they should. With both rears locking and the fronts working (but not locking) im confused about what could be causing the problem. Perhaps its the tyres? They are MT style so not the greatest on road grip, with the weight being thrown forwards are the rears being unloaded sufficiently to cause the skidding...? Or am i missing a G(?) valve or something in the system that splits the breaking forces? Ill let them bed in over the week and re adjust. Suggestions and ideas welcomed though Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted October 11, 2011 Author Share Posted October 11, 2011 Brakes failed today.... Fun Fun Fun! Believe it to be the master cylinder, but thats for another thread i guess.... ( no pressure on pedal, goes to the floor) Update on the drum locking shenanigans: Well when braking heavily the rears still lock. And it went from both locking back to just being the one again (drivers side). Next port of call i think is this G Valve. Didnt think i had one, but when the brakes failed today a more detailed look at the front end of the braking system (this time with the workshop manual in hand!) i discovered that yes i do actually have a G-valve. Its the valve with a ball in it that 'rolls up the hill' to decrease the power going to the back under fierce braking. So, can these G Valves be taken apart and cleaned etc to get them working again, or is it a case of having to buy a new one.... Anyone have the part number to hand?? Or are they fairly reliable so am I barking up the wrong tree.... Oh... then again, I guess if the master has been failing and not providing enough power to the fronts then all the force could be going to the back.... Thoughts? Quote Link to comment Share on other sites More sharing options...
western Posted October 11, 2011 Share Posted October 11, 2011 maybe the G valve on top face of the right chassis rail near the bulkhead is sticking/faulty, it's meant to prevent the rear brakes locking up under braking. Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted October 12, 2011 Author Share Posted October 12, 2011 Master was corroded/pitted, hence brake failure. New cylinder on order and will hopefully be fitted on saturday. If rears still lock, ill have a look at the G Valve. Prefereably aim to refurb it if possible as replacements (unsure of part number so might be wrong) are damn expensive! Quote Link to comment Share on other sites More sharing options...
Eightpot Posted December 12, 2011 Share Posted December 12, 2011 Did you get to the bottom of your rear drums locking up? I'm having the same problem with a drum-braked 110 I've just acquired and am suspecting it may be the G-valve as the front calipers seem to be working ok. It's just failed the MOT because of the locking up under fairly moderate pressure, and I'm wondering if it's the kind of thing I can remove, clean out and replace or if I'd better get a new one on order quick before the retest.. Quote Link to comment Share on other sites More sharing options...
SH4RKY Posted December 23, 2011 Author Share Posted December 23, 2011 Not yet. It still locks. I never got round to looking at the Gvalve, but its on my 'to-do' list. Although, according to the handbook (at least my interpretation of the book, please correct me if im wrong here), the G valve is a pretty simple thing, it uses the force from the decreasing momentum of a braking vehicle to move a ball bearing 'up a slope' to limit the amount of fluid going to the rear brakes.... If it requires the vehicle to be moving, can it be tested on a machine??? But yeah, as i say, G valve is on my to do, probably when the weather gets a touch warmer Quote Link to comment Share on other sites More sharing options...
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