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Brake Problem

Discussion in 'T3 & T4 Tech Help Clinic' started by AC-T3, Jun 19, 2020.

  1. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
    My '82 has developed a problem where the rears seem not to function correctly. Front rotors, pads and rear drums, shoes and cylinders where replaces not too long ago. Now excessive pedal pressure is needed to lock up the fronts, while the rears seem just dawdle. The hand brake is week also. The servo, vacuum lines and non return valve are all working and pressure tested to prove they hold vacuum. Now wondering if the brake pressure regulator is crook or if the shoe compound is too hard?
     
  2. Barry

    Barry Well-Known Member

    Messages:
    4,863
    Location:
    Abbotsford NSW
    Maybe rear shoes not matching the drum and only a portion is binding?
     
  3. grumble

    grumble Well-Known Member

    Messages:
    1,191
    Location:
    Taree
    Does the pedal sink when you start the vehicle with the foot on the brake, it should sink a little as the booster vacuum assists the brake pedal force? I have seen the vacuum hoses suck in allowing very little vacuum into the booster. Another couple of possibilities are the master cylinder, flexible brake hoses (these are getting older now & will close up internally) I assume that the handbrake was backed off completely before the rear brake shoes were adjusted initially, given a few pumps on the pedal, readjusted and then the handbrake adjusted.
     
  4. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
    Yes, one of the possibilities. Drums do get warm/hot after use.
     
  5. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
    Thanks Grumble, yes to all the questions and thanks for the extra leads. Have read on theSamba and others of old lines, things and pressure regulator accumulate moisture, gunk and grunge The plot thickens.
     
    grumble likes this.
  6. Dapom

    Dapom Well-Known Member

    Messages:
    750
    Location:
    Brisbane
    I’m sure that all of the items I’m going to mention will be covered but..... have you done a full fluid change? Are the adjusters in the rear drums definitely both in the correct orientation? On a final note if you end up having to crack the system I highly recommend putting in braided lines. I have the goodridge ones mine and they made a huge difference.
     
  7. cbus

    cbus Well-Known Member

    Messages:
    12,821
    Location:
    sunshine coast
    Seems there may be two different lengths of rear cylinders.

    Talking to someone this week who was fitting new slaves to rear brakes and the originals were 20mm longer ( end to end of pistons) than the replacements.
    But all suppliers only had the shorter version .

    Don't know if this can make a difference but seemed a safe option.

    The other issue in your situation.
    Is self adjuster working?
     
    Dapom likes this.
  8. grumble

    grumble Well-Known Member

    Messages:
    1,191
    Location:
    Taree
    I found that a few years ago ( back when I was still working) and got around it by adding a tab in the slot of the piston as I had seen fitted on some other vehicles. Fitted properly they take up the free play between the piston & shoe but they have to be locked securely in place or things get interesting (nasty). I don't think that is his problem because he hasn't got a low pedal 1st stroke & better on the 2nd stroke. I still lean towards the brake hoses other than that master cyl but not knowing the vehicle at all these are only suggestions.
    As an after thought have you tried with the booster hose disconnected YOU WILL a REMOTE AREA WITH NO ONE OR ANYTHING TO CRASH INTO FOR THIS AS THE PEDAL PRESSURE WILL BE A LOT HIGHER THAN NORMAL.
    Drive a short distance at a low speed with the booster hose on, mark the stopping distance,remove and block the hose, drive the same route with the same brake application point and compare the results. With the booster should be a lot shorter than that without and the pedal without should also be harder.
    If you are not sure take the vehicle to a licenced repairer. Again no responsibility accepted any decision to try this is to be made is made by you.
     
    Last edited: Jun 21, 2020
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  9. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
    Thanks to all for the assistance. I'm off the see Joe at Brisbane Water Brakes. Joe drove it, checked things out last week and confirmed booster, vacuum and fronts were OK, rears weak and asked that I seek forum advice on possible T3 quirks. Will let you know how it goes.

    Thanks again.
     
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  10. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
    Brake problem has been fixed after rears were rebuilt for the second time in 9 months!!!!!!! The problem was the brake shoes. They had turned a dirty black colour, were hard as steel and couldn't be scratched with a sharp object. Consequently the drums had been glazed to a super shiny mirror finish with the net result being next to no friction. But wait, there's more. When the wheel cylinder dust covers were pulled back, the 9 month old cylinders were weeping AND the bores showed early signs of corrosion. Cylinders were new, correct part number, with bore and stroke measured as per spec. All parts used in the previous rebuild were new, installed correctly and sourced from reputable volks parts purveyors in Sydney.

    Ah well, it is all done now and as Willy Nelson said, "back on the road again ......."
     
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  11. Syncro27

    Syncro27 Well-Known Member

    Messages:
    6,445
    Location:
    Terrigal, NSW Central Coast
    Time for a rear disc brake conversion:D

    My syncro gave me endless handbrake and general poor braking issues until they were upgraded to the T4 rear disc version. No issues since. No leaking wheel cylinders :)
     
  12. grumble

    grumble Well-Known Member

    Messages:
    1,191
    Location:
    Taree
    It is always good to see an end result. Usually brake shoes and drums with high polish point to driving with the hand brake partially on or the rears incorrectly adjusted.
     
    Last edited: Jun 30, 2020
  13. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
    Nah. Prior to initial rebuild the handbrake worked fine, fronts and rears stopped on a dime. Happy with drums thanks.
     
  14. AC-T3

    AC-T3 Well-Known Member

    Messages:
    1,025
    Location:
    Woy Woy
     
  15. Syncro27

    Syncro27 Well-Known Member

    Messages:
    6,445
    Location:
    Terrigal, NSW Central Coast
    Each to his own Rob.
     
  16. oldman

    oldman Super Moderator Staff Member

    Messages:
    9,559
    Location:
    Avalon Beach NSW
    That’s my next splurge Scott.....parts getting put together now ;)
    Cheers,
    Mark
     
    Last edited: Jun 30, 2020
    Syncro27 likes this.
  17. KahunaKombi

    KahunaKombi Super Moderator Staff Member

    Messages:
    21,385
    Location:
    Bracken Ridge, Qld
    Sounds familiar but with the Type3 ..... the dia / size of the rear cylinders need the smaller size to a Beetle which are larger and they will actually blow and start leaking fluid if installed in a Type3.
    Found this out from Mick Duffy aka Mick Motors (respected mechanic when the workshop was open) .... he just rattled off the 2 sizes and was baffled as to why the Type3 while having larger rear drums needed the smaller brake cylinder.
    So with the correct cylinders installed and a new set of rear brake shoes and clean and hone of the drums the rear brakes worked as they should have ...... just one of those things you can't pick up on inspecting a car without getting underneath and knowing what to look for with brake fluid weepage.
     

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