Major brake failure.

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Safeman23

Member
Posts
28
Location
Isle of Skye
Had a near death experience the other day when all the brakes on the Freelander failed to work. This happened on a French Auto route at speed. The master cylinder had bled out through a cylinder failure on the a rear wheel. I thought the Freelander had a dual circuit front/back system which prevented total brake failure. After a strip down I found that the rear shoe had jumped off the slave cylinder allowing he piston to pop out of the cylinder. There were no warning lights on the dash. If anyone can tell me why this happened and the possible reason why all the fluid bled out of the master cylinder ( does it have 2 reservoirs ) I would be extremely grateful.

Thanks

Safeman
 
ha, not so safeman then...

there is only one reservoir which serves both circuits. they are indeed diagonally split such that a failure of one circuit does not affect the other. however, they rely on there still being fluid in the system to work.

one other thing to check is the level switch on the fluid reservoir. think they all have a switch on the top of reservoir which brings up a red warning light on the dash when the fluid falls below the minimum level, which should have given you notice that something was up long before the fluid fell to a critical level.
 
Wow...lucky escape, as Optimus suggested, it seems like theres been a shortage of fluid in the first place. For the rear brake shoe to jump from the cylinder I woukd guess that one of the retaining pins would have to have failed. There should be two on each shoe to keep them securely against the backplate.
 
Wow...lucky escape, as Optimus suggested, it seems like theres been a shortage of fluid in the first place. For the rear brake shoe to jump from the cylinder I woukd guess that one of the retaining pins would have to have failed. There should be two on each shoe to keep them securely against the backplate.


Think you'll find that when the drums on there isn't much movement to allow that to happen. Probably down to fluid contamination and little or no maintenance causing the friction material to break up and the shoes to over travel.
 
Thanks everyone. I changed the shoes before I set off for France Used Delphi shoes. Good point about the fluid indicator. Will check that. I guess its a short across the terminals to operate the lamp. As far as the shoe retaining pin is concerned I remember there being only one fitted to each shoe. Its a shame that the garage who did the work dumped the bits before I picked the car up. If the shoe retaining pin did fail would there be enough room inside the drum for the shoe to move away from the top of the piston? Cant see the point of having a common fluid chamber for both circuits.

Thanks

Safeman
 
Thanks everyone. I changed the shoes before I set off for France Used Delphi shoes. Good point about the fluid indicator. Will check that. I guess its a short across the terminals to operate the lamp. As far as the shoe retaining pin is concerned I remember there being only one fitted to each shoe. Its a shame that the garage who did the work dumped the bits before I picked the car up. If the shoe retaining pin did fail would there be enough room inside the drum for the shoe to move away from the top of the piston? Cant see the point of having a common fluid chamber for both circuits.

Thanks

Safeman

The Freelander uses a pretty standard diagonal split circuit as OP has said. The warning light, or lack of it is the key here. If you had a warning, you would have checked the fluid level before it had fallen to the danger point.
Take it back to the garage that did the work and get them to fix it properly. There is only 1 shoe retainer per shoe from memory.
 
There is not enough room inside the drum to allow the piston to push the shoe so far out, that piston overtravels. This shoe was not installed properly, and the shoe never had the right contact with the piston. Piston overtraveled, and the fluid leaked out.

Garage that did the work is at fault, and it could've been fatal. :eek:

Or,......maybe you have some enemies that want you dead? ;)

Work on your own brakes, your life depends on them. Trusting your life to some grease monkey, getting minimum wage in the local garage, is not a good idea.
 
Similar thing happened to me.
The shoe retaining pin fell out leaving the clip inside the drum. The shoe came off the piston causing the brakes to fail, no pressure due to fluid leaking from the over extended piston.
Luckily at about 10 mph round the corner from work!
Repeated applications of the brakes in the failed state cause a loss of fluid from the now over extended rear piston.
An interesting situation all the same!

Chris
 
Apologies I just saw mistake in my own post...should have been two clips in each drum...one on each shoe, thanks Nodge. Appreciate what Diesel Do comments about movement of shoes within drum especially as the shoes tend to wear themselves a groove in the drum. However you can see from CJKs experience that this scenario with the retaining pins breaking away is possible. The retaining pin heads tend to corrode and this could easily go un-noticed until they fall through into the drum.
I agree totally with Danielsand regarding maintenance. I was once of opinion that I would leave my brakes to the experts. After continous problems with rear brakes and being told by "brake experts" that everything was in good order I went ahead and opened them myself, finding rust, dirt, deposits, missing spring, RETAINING PINS heads almost completely gone, no anti- seize on contact areas between backplates and shoes...etc. I didnt dive in knowing nothing, im an engineer by profession and used garages etc so that I could spend my time off with kids but now I make time to do my own work. Every part is there for a good reason.
 
Now you say it's had new shoes just before! I have seen shoes incorrectly fitted where they aren't in the grove on the piston and it's trapped behind using the rubber seal groove instead. That was only will power stopping the piston falling out. It was making odd noises cos the shoe was ****ed and rubbing. If it was left much longer it would have worn down and the piston dropped out. That was DIY brakes! So you can't win :)
 
Apologies I just saw mistake in my own post...should have been two clips in each drum...one on each shoe, thanks Nodge. Appreciate what Diesel Do comments about movement of shoes within drum especially as the shoes tend to wear themselves a groove in the drum. However you can see from CJKs experience that this scenario with the retaining pins breaking away is possible. The retaining pin heads tend to corrode and this could easily go un-noticed until they fall through into the drum.
I agree totally with Danielsand regarding maintenance. I was once of opinion that I would leave my brakes to the experts. After continous problems with rear brakes and being told by "brake experts" that everything was in good order I went ahead and opened them myself, finding rust, dirt, deposits, missing spring, RETAINING PINS heads almost completely gone, no anti- seize on contact areas between backplates and shoes...etc. I didnt dive in knowing nothing, im an engineer by profession and used garages etc so that I could spend my time off with kids but now I make time to do my own work. Every part is there for a good reason.


If you went to a "brake expert" that tends to indicate a fast fit type place? A lot of the guys in there aren't qualified mechanics. They get sent on a day or two brake training course, that gives them the title of brake expert but with no experience to back it up! This is what the likes of kwik fit do, they also have a qualified mobile guy that has a load of branches in his patch and he goes around sorting out the #### ups!!!
Having worked next door to one and seeing the damage they are capable of doing I'd steer well clear. Most apprentices at proper garages are far more capable.
 
if you put new retaining pins in make sure they are the proper ones as on the normal ones the heads are to small so make sure they are the ones for your car.
 
If you went to a "brake expert" that tends to indicate a fast fit type place? A lot of the guys in there aren't qualified mechanics. They get sent on a day or two brake training course, that gives them the title of brake expert but with no experience to back it up! This is what the likes of kwik fit do, they also have a qualified mobile guy that has a load of branches in his patch and he goes around sorting out the #### ups!!!
Having worked next door to one and seeing the damage they are capable of doing I'd steer well clear. Most apprentices at proper garages are far more capable.

You're bang on mate...it was such a place and ive learnt my lessons since. I would also agree you should only diy stuff if competent and have some technical ability. It is a bad situation to think many places may not be the experts they claim to be. As you mentioned, there are usually some proper experts on hand or available to these workshops. In situations such as my previous dilemma where the brakes are obviously not right id say its not really acceptable to say " cant find anything wrong therefore everything must be hunk dory" and hand the keys back. They should have consulted someone more able.
 
Hi All

Now had time to re-assess what happened. We had a need to brake pretty hard with the van on the back causing rear wheel brake lock up. It cleared its self but the hand brake travel was reduced. Not sure this was a factor.
Had an email from the LR garage who did the repair work down in Montpellier. He says the front of the shoe that sits on top of the piston had failed due to metal fatigue He has kept the shoe as an example of what happens when you fit non standard LR parts. Pictures on the way. I wonder what Delphi will say to that!
Will post when I get it.
 
It sounds to me that the shoes were not adjusted properly after fitting.
This would account for the extra movement needed by the cylinder and also the
extra stress put on the leading edge of the front shoe.

The Dealer is talking rubbish about the quality of Delphi Shoes.
Who are the OE suppliers to Landrover?
 
Hi All

Now had time to re-assess what happened. We had a need to brake pretty hard with the van on the back causing rear wheel brake lock up. It cleared its self but the hand brake travel was reduced. Not sure this was a factor.
Had an email from the LR garage who did the repair work down in Montpellier. He says the front of the shoe that sits on top of the piston had failed due to metal fatigue He has kept the shoe as an example of what happens when you fit non standard LR parts. Pictures on the way. I wonder what Delphi will say to that!
Will post when I get it.

Hand brake travel was reduced because the left shoe was almost in full contact with the drum at all times. Piston got overextended either behind the shoe, or in front of it. It stayed in that position wedged on the side of the shoe. By working the hand brake in that condition, you might've broke the tip of the shoe. Extended piston caused the seal to fail, and the fluid leaked out.

I think that's most likely what happened. And the initial reason for all this, was improper adjustment of the shoes on instalation.
 
Very interesting thread.

I tend to procrastinate a lot when I come to do work on my cars - I want to understand how things work and possible scenarios and the outcomes of failure. Means I might drink a lot of coffee before I actually take spanners to things :)

Brakes are obviously no exception because there's obvious horrendous outcomes for failure. This thread makes me think that coffee is well worth while :)
 
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