504 brake bleeding
  • Register
  • Help
Results 1 to 12 of 12
  1. #1
    Tadpole
    Join Date
    Nov 2010
    Location
    Stanthorpe, Qld
    Posts
    9

    Default 504 brake bleeding

    Hi There Fellow froggers, after a lengthy agony of bleeding the clutch slave cylinder on my '78 504 I finally achieved a result... Part of my problem was having a novice help with the bleed. I'd run a bleeding line from the left front brake nipple to the slave cylinder and asked the helper to pump the brake slowly, He, thinking we are working on the clutch gave a very fast series of pumps before I could get down to observe and forced a large amount of air into the system... I was able to bleed this air out from the front brakes but the back ones steadfastly refuse to give any joy at all. Initially I had the rear end up on blocks before RTFM... any Ideas would be of great help. in the words of John Wayne "We're burning Rego"
    Again thanks to all who have previously helped me with maintenence

    Advertisement

  2. #2
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    19,211

    Default

    Quote Originally Posted by Seamus Duffy View Post
    Hi There Fellow froggers, after a lengthy agony of bleeding the clutch slave cylinder on my '78 504 I finally achieved a result... Part of my problem was having a novice help with the bleed. I'd run a bleeding line from the left front brake nipple to the slave cylinder and asked the helper to pump the brake slowly, He, thinking we are working on the clutch gave a very fast series of pumps before I could get down to observe and forced a large amount of air into the system... I was able to bleed this air out from the front brakes but the back ones steadfastly refuse to give any joy at all. Initially I had the rear end up on blocks before RTFM... any Ideas would be of great help. in the words of John Wayne "We're burning Rego"
    Again thanks to all who have previously helped me with maintenence
    Don't have the rear wheels hanging when you bleed. The braking equaliser valve will cut off fluid flow to the rear brakes.

    Best to put bricks under the wheels and have the weight of the car on the wheels.

    You make a one man bleeding kit from an old fuel pump. Hook the inlet up to an open bleed nipple so when the push the pedal down the fluid passes through the pump. When you let the pedal go up, the pump check valve stops air being sucked into the system. I mounted my pump on the top of a glass screw top jar. The outlet goes into the jar (under the fluid level)

    This was designed, after having an argument which nearly caused a marriage breakdown, when my my wife helped me.
    Last edited by robmac; 15th April 2011 at 02:47 PM.

  3. #3
    Fellow Frogger!
    Join Date
    Mar 2011
    Location
    Kendenup WA
    Posts
    124

    Default

    Sure, with Robmac's suggestion of the old fuel pump you'll get a workable result -- but not the best possible. By reason of the suction created by the return movementof the pedal, small amounts of air are sucked in via the threads of the bleed screw and caliper body ensuring a, still, slightly spongy feel to the brake pedal.
    Professionals use a pressure system applied to the master cyl. or a vacuum system connected to the bleed screw.
    You could lash out $70 for a Gunsons pressure kit, which does the job, or make your own up.
    Fit a screw type tubeless tyre valve to the m/cyl. cap [blocking off the breather hole] and connect it to your spare tyre with clear plastic tubing. Importantly have only 15 PSI air pressure in it. Opening each bleed screw for a couple of seconds usually does the job. Needless to say it works with hydraulic clutches as well.
    I use this method on 2 tractors and 3 cars we have -- including our '92 505 GTi.

  4. #4
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    19,211

    Default

    Quote Originally Posted by Pavel Moore View Post
    Sure, with Robmac's suggestion of the old fuel pump you'll get a workable result -- but not the best possible. By reason of the suction created by the return movementof the pedal, small amounts of air are sucked in via the threads of the bleed screw and caliper body ensuring a, still, slightly spongy feel to the brake pedal.
    Professionals use a pressure system applied to the master cyl. or a vacuum system connected to the bleed screw.
    You could lash out $70 for a Gunsons pressure kit, which does the job, or make your own up.
    Fit a screw type tubeless tyre valve to the m/cyl. cap [blocking off the breather hole] and connect it to your spare tyre with clear plastic tubing. Importantly have only 15 PSI air pressure in it. Opening each bleed screw for a couple of seconds usually does the job. Needless to say it works with hydraulic clutches as well.
    I use this method on 2 tractors and 3 cars we have -- including our '92 505 GTi.
    With earlier type Peugeot cars it is next to impossible to "seal the master cylinders". Not all owners who value the originality want a schraeder valve sticking out of the master cylinder reservoir.

    On 404 clutch masters it's impossible to gain a seal because the cap is non sealing by design, so is the body.

    Personally, I've never had an issue with air being sucked in when using my "fuel pump" method, but some teflon tape on the nipple threads would solve the issue if it were to emerge.

    I certainly would not leave a car with "slightly spongy feel to the brake pedal"- the is always rock-hard.

    And the cost is still zero for the bleeding equipment, junk from the workshop. Often simplest is best.

  5. #5
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,488

    Default

    How are you bleeding them?? If you have two people all you need is a spanner. From the bleed nipple **you** control the bleeding.... Is this how your doing it?

    1--yell out "Pump the peddle and hold it down hard"
    2--crack the bleed screw open and let air/fluid come out.
    3--close bleed screw
    4--yell out "Let the peddle up, pump and hold the peddle down hard"
    5--go back to setup 2

    keep cycling through this process until there is no air left.

    it sounds to me like your letting them lift the peddle up before you have closed the bleed screw, so they are introducing air back into the sytem. Lift the @rse end by the diff or suspension... don't let the rear wheels hang down with the body jacked up. Any load sensing valves will close stopping fluid flow to the rear (back the rear of the car up onto ramps is probably easiest), add lots of weight into the boot to compress the rear suspension if your still not getting much fluid to the back.

    Also if you have rear drums, make sure they are adjusted until they are *just* dragging, otherwise you introduce a huge amount of "movement" into the brake pedal as the rear pads move out until they touch the drum

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/citro%EBn-forum/90325-best-project-car-you-have-ever-seen.html
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  6. #6
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,426

    Default

    Quote Originally Posted by DoubleChevron View Post
    How are you bleeding them?? If you have two people all you need is a spanner.
    Thats poor advice. Almost every wheel these days has a painted finish so ad a piece of clean tube and a glass jar to not only capture your paint stripper, but to veiw it as it comes out.
    A 'brake bong' is simply a glass with a tube. One end of the tube fits over the nipple with a tight seal and the other goes into the jar below the tide level so no air gets sucked back to fool you ino thinking it needs more bleeding.
    How much are brake bleed nipples??? Bugger all so do yourself a pre-emptive favour and do as the brake shops do and replace them before they cause trouble.

    I changed fluid colours on my last bleed so with the glass jar it was easy to confirm a full bleed had occurred.Went through 2 and a bit bottles of fluid this time.

    I replace my fluid yearly at rego time now, and last month we sucked all the old fluid out by vacuum, then re bled all the wheels the old way with a brake bong.(on a hoist I might add, I dont do brake bleeding or gearbox oil on the ground anymore).

    Of course my worst fears were realised this time. I should have got him to pump and me to bleed, or told the mech to take small dumps of fluid so my master cyl did not exceed its usual travel, but I didn't and it did, so now that my master is leaking I can do it all again next week when the new master turns up in the post.
    I should be getting good at it soon.


    Jo

  7. #7
    Real cars have hydraulics DoubleChevron's Avatar
    Join Date
    May 2000
    Location
    Ballarat,Vic,Aust.
    Posts
    16,488

    Default

    windscreen washer tube is ideal for bleeders I have found. all I meant was you don't actually need any of those flashy bleeder, two people will do a really good job at brake bleeding, it's only difficult if your by yourself.

    I don't bleed dodgy "master/slave" cylinder brakes often. All my cars have proper high pressure braking systems with mineral oil in them (that doesn't take up moisture).

    You can buy "easy bleeders" that have a one way valve in them if your struggling. It would make sense if your doing annual fluid changes.

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

  8. #8
    1000+ Posts jo proffi's Avatar
    Join Date
    May 2003
    Location
    sydney
    Posts
    8,426

    Default

    Quote Originally Posted by DoubleChevron View Post
    .... all I meant was you don't actually need any of those flashy bleeder, two people will do a really good job at brake bleeding, it's only difficult if your by yourself.
    That statement might only apply to people you are not married to.

    Jo

  9. #9
    1000+ Posts Beano's Avatar
    Join Date
    Mar 2004
    Location
    Brisbane
    Posts
    3,147

    Default

    Fluid not coming out of rear brakes ? Often it's just because the inner hole on the bleeder nipple is rusted up. Completely unscrew the nipple and try to suck through it (it's easier to see if there's a blockage than blowing). If blocked, the tiny inner hole needs a pin stuck through it. It's only about 1mm wide...
    Sometimes I use a tiny drill bit.

  10. #10
    Fellow Frogger!
    Join Date
    Mar 2011
    Location
    Kendenup WA
    Posts
    124

    Default

    Yeh, well each to his own, Robmac.
    Before the 505GTi we had an STi, and before that a 405 -- I had no problem sealing the cylinder tops. And to state that the 405 clutch master cylinder fluid is 'unsealed' is plainly ridiculous as that implies that it can both leak fluid and/or allow the ingress of air. Certainly, a high external air pressure should not be used -- but I was able to use between 5 & 10 psi quite successfully. I also have the same problem with a Deutz remote m/cyl. fluid container -- useing common sense, re pressure, has not caused the un-clipped supply hoses to to blow off.
    And who said anything about leaving a valve permanantly in the cap? If you haven't got a spare cap -- put a rubber bung in it.
    And why bugger around, with fluid dripping all over the place whilst applying PTFE tape to the bleed screws, when a clean, inexpensive and foolproof one-man semi automated system is simple to set up and use?
    Besides, assuming that for the rest of your life you will own a car, or cars, the hygroscopic nature of Dot 3 & 4 brake fluid ensures that it should be changed every 2 years or when the front pads/shoes are re-newed. Therefore the 'expense' is as justified as spanners, axle stands and wheel ramps --especially as storage is minimal.
    Still, some people prefer complexities rather than KISS.

  11. #11
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    19,211

    Default

    Quote Originally Posted by Pavel Moore View Post
    And to state that the 405 clutch master cylinder fluid is 'unsealed' is plainly ridiculous as that implies that it can both leak fluid and/or allow the ingress of air.
    Best to read the post rather than deliver a tirade (or look at the avatar).

  12. #12
    1000+ Posts Beano's Avatar
    Join Date
    Mar 2004
    Location
    Brisbane
    Posts
    3,147

    Default

    Oops......somebody's having humble pie for lunch.
    Oh well.....we're only human.

    To sum up, bleed rear brakes without the rear end jacked up. If no fluid appears, unscrew a bleed nipple and see if you can suck any air through it. If not, poke a pin or something similar through the tiny hole in the bottom. Sometimes it's hard to actually SEE this hole, as it gets rusted up easily.
    Last edited by Beano; 18th April 2011 at 02:15 PM.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •