404 brake saga - Page 2
  • Register
  • Help
Page 2 of 3 First 123 Last
Results 26 to 50 of 57
Like Tree1Likes

Thread: 404 brake saga

  1. #26
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by robmac View Post
    I'd be taking a good look at the master and the flexible hoses then.

    The hoses can can be economically reproduced by any brake shop with a Brakquip hose making machine.

    The 404 hose ends are a standard off the shelf fitting. Just take the original hoses to the shop.

    Advertisement


    You can even have road legal braided hoses in lieu of standard neoprene.
    Thank you for this, I will follow it up. Repco also had a listing of some compatible hoses from a few of the H series Holdens that matched.

  2. #27
    Fellow Frogger! Artificer's Avatar
    Join Date
    Mar 2018
    Location
    Robina
    Posts
    122

    Default

    so I am inclined to just start replacing stuff with new bits, on the basis that this can't be a BAD thing.
    Chasing rainbows is NOT a good idea & simply wasting money.
    Especially replacing good parts with similarly good ones.
    We have been told you have done something with the master cylinder, booster &/or brake lines.

    Things like replacing brake hoses is last on anything like this as they were not interfered with & can easily be eliminated from the brake circuit 1 by 1, if suspected of being crook. BTW they do have a service life & it is not 30 or 40 years!

    Forget the guessing [or following unqualified guesser's] & start diagnosing.

    Suggest this process would be easier for yourself, & those trying to assist, if all the symptoms were listed then ticked off as eliminated. Currently all symptoms are commingled & thus hard to address logically.

    This is most likely something/s that has/have been introduced/replaced by work that has been done on the brake system recently.
    So first thing to eliminate as a possible contributor is the foreign to this system is the hydrovac.

    1. Test the hydrovac is functioning.
    Switch off engine & pump pedal then hold.
    Start engine & pedal should feel softer/sinking when engine vacuum assist to the hydrovac is received.
    2. The VH40 & 44 came in different setups primarily for single circuit master cylinders.
    2a. Front & rear circuits will be divided after coming out of the booster & when fitted with rear drums there is a possibility a residual pressure valve & pressure differential valve will be fitted in the rear circuit/s.
    2b. The bore sizes can be larger/smaller from the original booster giving difference in pedal travel & effort.
    3. Inadvertently interchanging brake lines front to rear will give a rear brakes locking up before front symptom.
    This is because most braking force is meant to go to the front.

    Let's know what you find but if unsure take the hydrovac to a brake specialist for testing/checking.

  3. #28
    1000+ Posts
    Join Date
    Nov 2010
    Location
    tweed heads
    Posts
    1,483

    Default

    I have recently gone through the same thing on my 69 404 .my pedal went to the floor at a roundabout ,although the rear wheel cylinders looked ok ,when i pulled the rubbers back there was fluid seeping ,i replaced the cylinders and fitted a portioning valve i had had reconditioned ,all bled the pedal was crap ,the brakes jammed up and i could only force it to drive in reverse ,.the boost had been only just sufficient since i had the original completely rebuilt by better brakes ,i found the boost problem was due to the vac hose collapsing internally at the manifold end ,i got a 3 way junction from the brake place ,fitted it in place of the portioning valve ,blew the dust out of the rears ,bled again ,all is fine now with acceptable boost ,,i intend to swap the valve back in and see what happens ,as im not convinced it was the problem ,no matter what i did i couldnt get the spongy air in the system feel ,on the pedal till i removed the valve ,suspect there was air in it ,as i am now using it as a daily ,im having difficulty finding the time ,and i can only lock the rears when braking savagely , prior to this everything in the system had been replaced or re built except the rear cylinders ,calipers ,master hydraulic hoses ,portioning valve ,were done ,so all i can contribute is check the vac hose ,and swap out the valve with a three way ,to eliminate that as a problem ,at the time i suspected it must have had an air pocket in it ,causing the spongy pedal ,pugs

  4. #29
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    18,772

    Default

    A lot of good info in this post.

    I've added some page breaks so members will find it easier to read.



    I have recently gone through the same thing on my 69 404 .

    My pedal went to the floor at a roundabout ,although the rear wheel cylinders looked OK ,when I pulled the rubbers back there was fluid seeping .I replaced the cylinders

    And fitted a portioning valve i had had reconditioned ,all bled the pedal was crap

    The brakes jammed up and i could only force it to drive in reverse .

    The boost had been only just sufficient since i had the original completely rebuilt by better brakes ,I found the boost problem was due to the vac hose collapsing internally at the manifold end

    I got a 3 way junction from the brake place ,fitted it in place of the portioning valve ,blew the dust out of the rears ,bled again ,all is fine now with acceptable boost.

    I intend to swap the valve back in and see what happens ,as i'm not convinced it was the problem.

    No matter what I did I couldn't get the spongy air in the system feel ,on the pedal till i removed the valve ,suspect there was air in it ,as I am now using it as a daily ,I'm having difficulty finding the time ,and I can only lock the rears when braking savagely

    Prior to this everything in the system had been replaced or re built except the rear cylinders ,calipers ,master hydraulic hoses ,portioning valve ,were done ,so all I can contribute is check the vac hose ,and swap out the valve with a three way ,to eliminate that as a problem

    At the time i suspected it must have had an air pocket in it ,causing the spongy pedal

    ,pugs

  5. #30
    Fellow Frogger! Artificer's Avatar
    Join Date
    Mar 2018
    Location
    Robina
    Posts
    122

    Default

    Lots of pillar to post stuff going on & not diagnosing!
    That being said:

    It is very unusual for the brake pedal to go to the floor without progressively becoming worse.
    This 'progressively worse' is from lack of brake fluid, caused by leaking components, depleting the reservoir of fluid.

    Brake pedal going to the floor [& the reservoir level being OK] is generally related to a master cylinder primary cup fail/ing/ure issue.

    I've seen this in a number of older vehicles where the little brass shim was left out, somewhere along the line, between the primary cup & piston.
    The cup after years of operation resembled a bottle top.

    When the brakes are applied the closed brake system just doesn't close & the pedal goes straight to the floor or slowly sinks to the floor on hard application or standing @ a stop light with brakes on, for example.

    Bleeding air when a proportioning valve is in a brake circuit can sometimes be problematic, primarily as they alter fluid pressure between circuits.

    I would never recommend pump bleeding brake systems due to problems it can cause particularly with old non refurbished brake parts.

    Here is one good inexpensive [cheap old mechanical fuel pump] vacuum method I employ that will work from longest to shortest line.
    Use liquid teflon or thick paint around the bleeder if drawing air from there....when trying to pull the vacuum....

    PC290268.jpg

    Here is another method:
    https://www.youtube.com/watch?v=Af0SYcbzIbo
    Last edited by Artificer; 12th July 2019 at 10:47 AM.

  6. #31
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    OK, I've read all this.

    Just to be clear, the car is NOT losing brake fluid. There may well be some bypass happening on the master cylinder, but it passes every test I can throw at it in terms of maintaining pressure. It does appear to be needing to fill some other area of the system before it can do its job properly. And whatever it is doing, the fluid is (eventually) returning to the reservoir.

    I have done a lot of work on old car brakes in the past, so I am kind of shocked to discover that I cannot figure this one out without help. There have been some good suggestions here which I will follow up, but at this stage I am getting the impression that I am going to have to spend my way out of this a little. My hope that someone would come up with a "you've forgotten to twist the XYZ thingumy" solution was a long shot, but worth a try. I think the closest I can get to that would be the focus on the rear pressure limiter, not least because Robmac's description of his problem is so very similar to what I am seeing.

    I think I will start with Robmac's suggestion of temporarily removing the pressure limiting valve at the rear, as it is a cheap and simple solution.

    The job is tricky, I am forced to juggle multiple variables brought about because of the sequence of events and the multiple unknowns.

    1. I do not know how long it took for the extra travel problem to develop, as my son didn't really notice it. (Insert face-palm emoticon here.)

    2. I do not KNOW the condition of the VH40 booster or the original VH44.

    3. I do not know the condition of any of the parts, really, except maybe the master, which I have pulled apart and looks very good.

    I really liked the spray bottle idea, did not expect that to work as well as it appeared to do, so I will give it a try.

    Matt

  7. #32
    Fellow Frogger! Artificer's Avatar
    Join Date
    Mar 2018
    Location
    Robina
    Posts
    122

    Default

    Matt: How to adequately test the hydrovac was enunciated earlier & try bleeding properly before pulling anything apart, would be my suggestions. JG.

  8. #33
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    18,772

    Default

    Quote Originally Posted by Gilow View Post
    OK, I've read all this.

    Just to be clear, the car is NOT losing brake fluid. There may well be some bypass happening on the master cylinder, but it passes every test I can throw at it in terms of maintaining pressure. It does appear to be needing to fill some other area of the system before it can do its job properly. And whatever it is doing, the fluid is (eventually) returning to the reservoir.

    I have done a lot of work on old car brakes in the past, so I am kind of shocked to discover that I cannot figure this one out without help. There have been some good suggestions here which I will follow up, but at this stage I am getting the impression that I am going to have to spend my way out of this a little. My hope that someone would come up with a "you've forgotten to twist the XYZ thingumy" solution was a long shot, but worth a try. I think the closest I can get to that would be the focus on the rear pressure limiter, not least because Robmac's description of his problem is so very similar to what I am seeing.

    I think I will start with Robmac's suggestion of temporarily removing the pressure limiting valve at the rear, as it is a cheap and simple solution.

    The job is tricky, I am forced to juggle multiple variables brought about because of the sequence of events and the multiple unknowns.

    1. I do not know how long it took for the extra travel problem to develop, as my son didn't really notice it. (Insert face-palm emoticon here.)

    2. I do not KNOW the condition of the VH40 booster or the original VH44.

    3. I do not know the condition of any of the parts, really, except maybe the master, which I have pulled apart and looks very good.

    I really liked the spray bottle idea, did not expect that to work as well as it appeared to do, so I will give it a try.

    Matt
    A final thought 404s are known to develop free travel in their brake pedal linkages. This can manifest as lost travel when pushing the brake master.

    A quick look at possible wear in brake pedal linkages may be worth a look.

  9. #34
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,137

    Default

    404s are reknowned for the pedals to seize on their shaft. If the brake pedal doesn't return fully the master cylinder won't work as it should. Get under the dash and by hand check that the pedal returns fully without friction. If it is stiff you need to pull the complete pedal assembly out, knock out the shaft (without breaking the alloy housing) and clean and grease everything. You won't be able to simply spray with WD40 to fix it.
    Dano likes this.

  10. #35
    Fellow Frogger!
    Join Date
    Nov 2010
    Location
    Avisford NSW
    Posts
    540

    Default

    Reconditioned valves from me $220 exchange

  11. #36
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by ianrobbo View Post
    Reconditioned valves from me $220 exchange
    Good to know, thank you.

  12. #37
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by GRAHAM WALLIS View Post
    404s are reknowned for the pedals to seize on their shaft.
    I remember reading this a while back. But no, this is not the problem. Travelling very freely.

  13. #38
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by Artificer View Post
    Matt: How to adequately test the hydrovac was enunciated earlier & try bleeding properly before pulling anything apart, would be my suggestions. JG.
    Well, it's a bit late for that I'm afraid. As I said in my original post, I have actually SWAPPED the boosters. AND dismantled and inspected the master. AND bled the system.

    The boosters are both behaving perfectly in testing, this feels like something different, certainly something I have not met before. So much esoteric knowledge in any car, I think, from the advice here, that the regulator at the back is the next logical step. Simple enough to eliminate.

  14. #39
    1000+ Posts Beano's Avatar
    Join Date
    Mar 2004
    Location
    Brisbane
    Posts
    3,032

    Default

    Quote Originally Posted by Gilow View Post

    I have done a lot of work on old car brakes in the past, so I am kind of shocked to discover that I cannot figure this one out without help.
    I just got a flash of Schadenfreude. The same has happened to me twice recently, and I still have the second problem.

    The important things are to do things methodically and prioritize them, don't let it all stress you out, and leave a bit of time between each step for your mind (even your subconscious) to mull it over and pop up a solution.

  15. #40
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    18,772

    Default

    Quote Originally Posted by Beano View Post
    I just got a flash of Schadenfreude. The same has happened to me twice recently, and I still have the second problem.

    The important things are to do things methodically and prioritize them, don't let it all stress you out, and leave a bit of time between each step for your mind (even your subconscious) to mull it over and pop up a solution.
    As well as persistence and maintaining self confidence.

    I spent almost an hour yesterday diagnosing a fault in an electronic project I had just built. Only to discover I'd installed an LED backwards.

    The fault was found without test equipment and solely by careful inspection.

    I was most deflated after finding it.

  16. #41
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by robmac View Post
    I spent almost an hour yesterday diagnosing a fault in an electronic project I had just built. Only to discover I'd installed an LED backwards.

    The fault was found without test equipment and solely by careful inspection.

    I was most deflated after finding it.
    I can relate to that. Hooked up a DS18B20 temperature probe the other day. No reading.... still no reading... what's going on? Picked it up to see if warming it with my fingers would help... burnt my fingers.

    Oh yeah, they are 5 volts, not 12 volts. Wrong side of the regulator chip. Probe in the bin too.

  17. #42
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by Beano View Post
    .... and leave a bit of time between each step for your mind (even your subconscious) to mull it over and pop up a solution.
    Or for the Froggers to come up with a solution...

    But yes, I have walked away from it for now. My son is away for a week from tomorrow, so I have some time to tackle this carefully.

  18. #43
    1000+ Posts
    Join Date
    Nov 2010
    Location
    tweed heads
    Posts
    1,483

    Default

    PS clamping off the rear hose produced a good pedal and braking ,so the problem on mine was defiantly in the rear ,and i had just replaced the wheel cylinders complete ,thus swapped out the valve ,apart from a faulty cylinder theres not much else back there that can go wrong

  19. #44
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by pugwash View Post
    PS clamping off the rear hose produced a good pedal and braking ,so the problem on mine was defiantly in the rear ,and i had just replaced the wheel cylinders complete ,thus swapped out the valve ,apart from a faulty cylinder theres not much else back there that can go wrong
    There's an idea, I could just plug the outlet on the four-way at the front for testing.

  20. #45
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    18,772

    Default

    Clamping the torque tube brake hose requires no disassembly nor it is necessary to loose fluid or bleed the the the system.

  21. #46
    Member
    Join Date
    May 2015
    Location
    Adelaide
    Posts
    102

    Default

    Quote Originally Posted by robmac View Post
    Clamping the torque tube brake hose requires no disassembly nor it is necessary to loose fluid or bleed the the the system.
    Umm... ok, but I feel like that wouldn't be all that good for the brake hose?

  22. #47
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,137

    Default

    Quote Originally Posted by Gilow View Post
    Umm... ok, but I feel like that wouldn't be all that good for the brake hose?
    Especially as they are probably 50 years old.

  23. #48
    1000+ Posts Wildebeest's Avatar
    Join Date
    Oct 2004
    Location
    Perth Western Australia
    Posts
    2,674

    Default

    Slightly off topic. A tip given me back in my 404 days [sigh].
    If replacing the vacuum hose from the manifold to the booster allow for an upward loop in the hose to prevent petrol vapour finding its way into the booster diaphragm.

    Also experience severe brake locking on, bled off fluid at master cyl to get mobile only, not a fix. Replaced equaliser valve at axle*.
    Later, reasons unknown I replaced the original booster with a VH 44. Simple/tidy installation. Boost not as severe as original, approximated the same as none boosted drum type.

    *A bit wary of eliminating equaliser and fitting a "T". Was informed that brake lock up would occur ?

  24. #49
    VIP Sponsor
    Join Date
    Aug 2000
    Posts
    9,137

    Default

    Yes , removing equaliser will cause lock up. Original booster was meant for Thermostable drum brakes, too much boost for discs, dangerous really, but no worse than most new cars have these days. Maybe that's why ABS is fitted ? LHD 404s had a proper mastervac, but no room in RHD cars.

  25. #50
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    18,772

    Default

    Quote Originally Posted by GRAHAM WALLIS View Post
    Especially as they are probably 50 years old.
    If that is the case you may have found your problem. Any brake hose in serviceable (safe) condition will cope with sensible clamping.

Page 2 of 3 First 123 Last

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
  •