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Thread: Front brakes don't work!

  1. #11

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    Following the recommendation in an earlier reply I removed the front right drum. Found that the new shoes were showing wear marks, in the middle and on the ends of the shoes. The marks were not uneven side to side. I then had my wife press the brake pedal to check the travel of the pistons in the wheel cylinders. There was not a lot of travel....more in the top wheel cylinder ( front most shoe).....the bottom cylinder did not move until I put pressure on the front shoe to keep it from moving ( it still moved but had resistance from my hand). Neither the top or bottom cylinder moved alot. These are new wheel cylinders. Should there be a lot of piston travel without the drum in place? I've pretty well described the symptoms. What is wrong and what needs to be fixed so that the brakes work well enough to skid the tires if I needed to.

  2. #12
    Join Date
    Jul 2020
    Location
    UK
    Posts
    313

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    The cylinders do not have to move much to operate the brakes so I would not be concerned . They do operate which confirms they work. You will not get full braking until the shoes are bedded in and you get full contact over the whole of the shoes . Just keep using it and operate the brakes frequently in short bursts to bed them in. I remember back in the 1960's when I had a S2 diesel I overhauled the brakes, new shoes, cylinders etc and it took about a thousand miles to get really good brakes. . Girling who made the original brakes for Land Rover used to grind the linings after fitting to the shoes, to make them match the drum diameter. Which make of shoes are they, as I have heard of the wrong grade of linings being fitted? I am not sure if this helps, picture from Girling Bulletin on pedal travel . As yours is a later S3, 11" front brakes, the 109" figures would be more representative.
    Click image for larger version. 

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  3. #13

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    Thanks. I feel a bit more comfortable about the brakes. I still am puzzled by why the rear brakes get HOT while the fronts are cold after driving the S3. The adjusters are as "in" as they will go on front and back. I bought the shoes from Rimmer Brothers ( sorry RN but they were cheaper even with shipping and got here quickly). One box was Britparts the other Ferodo. I don't remember which brand went where ( front or back). Why two brands - had to do with availability during covid.

    Item 6 in the Girling Bulletin refers to a Figure 3. Can you forward that to me? My pedal travel is good.....and is firm.

    I will continue to drive and "bed" the shoes. Hope the braking improves and that this is the end of the saga

  4. #14
    Join Date
    Apr 2021
    Location
    SF Bay Area
    Posts
    239

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    @JVSsimmons, you said some stuff that rang a bell for me. You said you have 11” drums. You said you had a PDWL valve, (which you removed) and you talked about plumbing the MC “the right way” with front pipe going to front brakes, etc.

    I just did my brake system, and was all over the parts manual, so it’s fresh for me. That PDWL/Shuttle valve was for a 2 line system, and Vacuum Booster(I don’t know if your MC is backed by a Vacuum Booster/Servo, but guessing so). That points me to a year range between 73-85. Around 80, they switched piping on the MC…they flipped it. So the larger volume line is on the “farthest back” plug post 1980…and on the “front” pre 1980.

    Look at these two MC’s closely:
    1980+ type (front brake larger line on front pipe - yellow cap)
    https://www.roversnorth.com/parts/pl...ate_series_iii
    I put this one in.

    1971-1979 type (front brake larger line on rear pipe - red cap)
    https://www.roversnorth.com/parts/pl...dual_power_109

    1969-1980 SWB/88 type.
    https://www.roversnorth.com/parts/pl..._dual_power_88

    Find out which one you have. They look similar, and interchange (even if the parts guide says they are not to be used for different years…they fit. It’s the swapping of lines that makes the recommendation not to use them off years). Look closely at yours. In the aftermarket, the difference is:
    * The brassy body sticks out past the plastic reservoir (1980+)
    * The more squarish reservoirs (1980+)
    * The larger volume line will have a 7/16 DIM fitting on it (so you can’t normally swap lines by mistake) even though the line is the same thickness. You’ll see the “7/16” on the plastic cap of new ones.

    Like I said, because they totally fit, there’s nothing to stop a mechanic from putting the 1980+ one on there. I did, and it works great. But the lines swapped. If someone ran new lines, they wouldn’t know. So check that, because 11” drums have larger wheel cylinders and the front fork in a dual line system needs more volume. So, I suspect you might have all that volume going to your rear brakes instead, pressing them hard and getting them hot while the front are barely engaged.

    For what it’s worth, I have a brand new system(100% new components, including PDWL, all new pipes) and mine doesn’t lock up either. Stops great. But…it’s drums. So I say that because I think your rear brakes wouldn’t lock up due to over pressure. Drums just don’t normally do that. They’re not like disks.
    ...┌───────┬──,,
    ...|______OD__|__\\_____
    ...d ..__ .........° |°... | ..__....p
    »»└/ | \────┴──┴/ | \─┘≡
    ..../..@........................@

    1973 Series 3, 109

  5. #15

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    There has been more developments and I'm afraid this saga will continue. First, the new developments. Another Series owner stopped by last night and he and I discussed the brake issue... and went for short drive ( a little over two miles), during which we tested the brakes with some hard braking. When we got parked back in the garage the rear wheel was again HOT and the fronts cold. We then first looked at the adjuster - shoes were as "loose" as could be adjusted. Then we removed the drum - it came off easily with very little resistence. Ummm, then why is the wheel so HOT. With the drum of the axel was still difficult to turn ( emergency brake was not engaged) We then began to suspect that the wheel bearing may be too tight - both wheels felt hot; so could wheel bearings on both sides be too tight? Since, a half shaft was replaced by the shop I took it too earlier they may not have adjusted the bearings correctly or just ignored the adjustments, OR did not check or replace fluid in the differential. Now I have somethings to check: fluid level, bearing adjustments, emergency brake adjustment. Will get to all this this weekend.
    Now for the comments about the MC and plumbing. Thank you for the input. Unfortunately I do not know if the shop I took it to installed the correct MC. With the info you sent I will check. Obviously the colored plugs are no longer there as a guide. Without knowing which MC they installed I don't know if the plumbing as it now is, is correct or not. And to make sure I understand what you said: on Series 3 after 1980 the MC port for the front brakes should be at the rear of the MC...correct? I will look at the MC using the info you sent. Guess I could switch the lines where the shuttle valve use to be and see what I get. The Series owner that visited didn't think we drove far enough or brakes hard enough to heat up the rear wheels like we found. This saga may have multiple levels of problems to sort out: brake line plumbing, correct MC, wheel bearings, fluid levels. I appreciate the time and effort that all have contributed to helping me diagnose and correct the problems.

  6. #16

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    vlad_d, Attached is photo of my MC. It appears to be the correct MC. It has a 1 1/16 inch bore. The rear port does indeed have a 7/16 fitting. The front fitting is larger with a 13mm fitting. So, is the "larger volume line" on the rear port even though the fitting on the front is larger?

    Click image for larger version. 

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  7. #17
    Join Date
    Dec 2010
    Posts
    413

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    the only thing to keep the shoes from retracting is either fluid is not making it back into the master resevour. (tipping valve or shuttle, distance (clearance) in the master cylinder rod assy or maybe weak return spring on the shoes?

  8. #18

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    Quick note: U cannot switch the pipes 'cuz your pipes have different thread sizes [just so that can't happen!!] If your hub/wheel bearings got "that hot" they would lock up solid. Or screech like a banshee!!!! A LITTLE hot and U'r lucky. Superhot and most of that end of town will know about it. And U will 4 sure!!!! Been there!

  9. #19
    Join Date
    Apr 2021
    Location
    SF Bay Area
    Posts
    239

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    Click image for larger version. 

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    Yours looks like mine, the later one.
    Here’s how I hooked mine up. If you zoom in the pic you can see it going down to the PDWL/Shuttle valve.
    My PDWL valve is plumbed: front side to front brakes, back half to back brakes.
    On mine, it goes:
    MC rear to front circuit of brakes
    MC front to real circuit of brakes

    Hope this helps. I’m going to see if I can find something in the green bible that says that. I hate to give brakes advice without reference. Hang tight…
    ...┌───────┬──,,
    ...|______OD__|__\\_____
    ...d ..__ .........° |°... | ..__....p
    »»└/ | \────┴──┴/ | \─┘≡
    ..../..@........................@

    1973 Series 3, 109

  10. #20
    Join Date
    Apr 2021
    Location
    SF Bay Area
    Posts
    239

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    Agreed. You’d have to have a double flare tool and put a new flare fitting one, which I did when making up new lines.

    The reason I suggested this is…with old cars, you can’t guarantee what’s on there came that way from the factory. Any mechanic in the last 50 years could have changed it. So…you might not be able to trust the flare fitting on there. I mean pretty safe…but if you have phantom issues, this might be something to check.
    ...┌───────┬──,,
    ...|______OD__|__\\_____
    ...d ..__ .........° |°... | ..__....p
    »»└/ | \────┴──┴/ | \─┘≡
    ..../..@........................@

    1973 Series 3, 109

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