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C3 75 Breaks

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Old Jan 16, 2018 | 10:22 AM
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Default C3 75 Breaks

Hello Guys,

This a follow up of my C3 Blackout that you helped me to resolve some time ago. Now, I advance to next level: Breaks. I have automatic gear (that we guys from Europe are not so familiar with). When I start up the car, the pedal gets suddenly softer and lower to the floor, however, it breaks well and as I have checked carrefully, there is no leakage on breaks, everything is dry.

Break light on dashboard shines permanently.

I have a little leakage on connecting hoses to the steering booster, I believe that one is feeded from the smaller fluid tank on master cylinder? At least I think it is on stearing, it is under the engine behind front axel and it travels with steering rods. I have lost about the third of this tank over three month. Could this have any influence on breaks being aerated or on the shining break light? I have red something about a proportional valve here on forums but I not much clever from that.

Thanks a lot,
Jiri
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Old Jan 16, 2018 | 11:01 AM
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the light indicates a break problem, or if they have been worked on lately, it might need reset by pressing on the peddle very hard a couple of times ( resets the proportioning valve). OR the wire might be off the proportioning valve it self.
where are you in Europe??? I coming over in March to Amsterdam, doing a river cruise with Viking.
The light is also hooked up to the emergency brake, is it all the way down???

Last edited by lvmyvt76; Jan 16, 2018 at 11:02 AM.
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Old Jan 16, 2018 | 11:17 AM
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bummer
check the emergency brake
switch first.
the proportioning valve must have tripped.
wouldn't hurt to redo/check the whole brake system since
they are the only way to stop
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Old Jan 16, 2018 | 11:37 AM
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Hi, Many Thanks. She is currently located in Abu Dhabi, I do somewhat commute for work down here fron Prague. I try to inserte her picture hereby, not sure if succesful as I have never done it.

Couple of questions:
The tough break pedal pushing - with an engine off or on?

The parking brake sensor - where is this located and how easy/ difficult it is to get on it?

The proportional valve - where can I find it, below the tanks/ master cylinder?

I will most probably wilk have to take her to Sharjah as there are some vintage car mechanics opposite to Abu Dhabi where I only know official Chevrolett garage which is somewhat costly. It is abot 180 kilometers passing Dubai. Do I risk anything with steering mild leakage? I would tend believe that it should somewhat work even the leak gets worse? Or, is it pure hydraulics?

Jiri
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Old Jan 16, 2018 | 11:43 AM
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Now, The picture as promised. C3 1975, small block, 165hp, as I have identified from VIN number, T-top. Not a musscle car at all but for 10k bugs quite a fun!
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Old Jan 16, 2018 | 11:48 AM
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To be clear..I'm not the spelling police.
Brakes not breaks..I only say this because in the future when someone uses the search function, they won't find your thread (to benefit from, or to advise).
Steering not stearing same scenario.

Steering and brakes are two complete different systems.
Fading brake pedal may be caused by a faulty power brake booster (leaking vacuum).
Fluid loss in the powering steering reservoir, is due to a leak in the system.
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Old Jan 16, 2018 | 11:48 AM
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sorry, brakes are too important to
try and teach over a forum.
as far as peddle feel, no difference from any car.
no engine vacuum will make a hard to push peddle
but you won't notice because you are not moving.

spongy feel? air
goes to floor board? bad master cyl or lot of air
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Old Jan 16, 2018 | 11:55 AM
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Originally Posted by tokim
To be clear..I'm not the spelling police.
Brakes not breaks..I only say this because in the future when someone uses the search function, they won't find your thread (to benefit from, or to advise).
Steering not stearing same scenario.

Steering and brakes are two complete different systems.
Fading brake pedal may be caused by a faulty power brake booster (leaking vacuum).
Fluid loss in the powering steering reservoir, is due to a leak in the system.
Sorry for misspelling, a combination of East European guy and my googles not being with me:-( I will try better next time!
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Old Jan 16, 2018 | 12:11 PM
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Originally Posted by jkrch
Sorry for misspelling, a combination of East European guy and my googles not being with me:-( I will try better next time!
No need to apologize, I understand.
A lot of people (myself included) use the search function, so to be able to succeed in searches, the spelling becomes a factor.
Good luck.
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Old Jan 16, 2018 | 07:20 PM
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Hi Calwldlife,
If you have a spongy pedal when the engine is on, then you most definitely have air in the
brake lines and the system will require bleeding to remove the air. There is plenty of
information on the correct way to do this on the forum.
Nice looking 75.

Mark
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Old Jan 16, 2018 | 09:02 PM
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Originally Posted by jkrch
I have a little leakage on connecting hoses to the steering booster, I believe that one is feeded from the smaller fluid tank on master cylinder?
This sentence makes it sound like you have a hydro boost setup versus the stock vacuum boost. Can you post a picture of the master cylinder/booster area?

Pics of different types:

Stock vacuum booster


Hydroboost

Last edited by SteveG75; Jan 16, 2018 at 09:05 PM.
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Old Jan 17, 2018 | 07:23 AM
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Hi Steve & All,I have checked what I have under the bonnet and it is the vacuum one. I have also cleaned/checked on the steering leakage and it is only a very little one, no drop since yesterday, will have it fixed once I get her to the garage.On brakes: I have checked on, everything is dry, clean, master cylinder, calipers, wheels, I have even identified proportional valve mounted under the cylinder on the fender, wire is well fixed to it.When under the car, a red wire fallen down on me coming from engine space/firewall wire nest with loosened end under the car, ended up with a small rubber cap. I would tend to believe that this might be the wire from hand brake sensor? How the sensor works, it interrupts the loop when the hand brake is engaged? I will only be able to fix it when I can get under the car, she is either too low or I am too fat:-(When the car is off, the pedal can be pumped and hardened but not much, for about 1/4 of pedal lift and gets to the uper position. When I have my leg on the pedal and start up, it goes down for app. 1/3 of the lift and brakes normal in the second third of the lift. It cannot be pumped up. I would believe that it just needs bleeding and that it can be carefully driven to the mechanic. Nevertheless any objections are appreciated.Thanks,JiriFrom another barrel: when checking on wires, I have discovered the bonnet opening wire out of its lead and going through the nest of wires under the dashboard, a little while to cut them off and put the car to the fire or cut off one half of electrical systems! ... this a quality of Middle East engineering... that is why I need to understand the problem. When you come to a garage, you have to tell them what exactly you want them to do, otherwise they change half of the car and the original problem remains unsolved.
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Old Jan 17, 2018 | 07:27 AM
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Originally Posted by jkrch
Hi Steve & All,I have checked what I have under the bonnet and it is the vacuum one. I have also cleaned/checked on the steering leakage and it is only a very little one, no drop since yesterday, will have it fixed once I get her to the garage.On brakes: I have checked on, everything is dry, clean, master cylinder, calipers, wheels, I have even identified proportional valve mounted under the cylinder on the fender, wire is well fixed to it.When under the car, a red wire fallen down on me coming from engine space/firewall wire nest with loosened end under the car, ended up with a small rubber cap. I would tend to believe that this might be the wire from hand brake sensor? How the sensor works, it interrupts the loop when the hand brake is engaged? I will only be able to fix it when I can get under the car, she is either too low or I am too fat:-(When the car is off, the pedal can be pumped and hardened but not much, for about 1/4 of pedal lift and gets to the uper position. When I have my leg on the pedal and start up, it goes down for app. 1/3 of the lift and brakes normal in the second third of the lift. It cannot be pumped up. I would believe that it just needs bleeding and that it can be carefully driven to the mechanic. Nevertheless any objections are appreciated.Thanks,JiriFrom another barrel: when checking on wires, I have discovered the bonnet opening wire out of its lead and going through the nest of wires under the dashboard, a little while to cut them off and put the car to the fire or cut off one half of electrical systems! ... this a quality of Middle East engineering... that is why I need to understand the problem. When you come to a garage, you have to tell them what exactly you want them to do, otherwise they change half of the car and the original problem remains unsolved.
... when reading it after I have to do a little explanation. The brake pedal is 3/4 up and it can be pumped the last 1/4 up hardening slightly...
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Old Jan 17, 2018 | 10:23 AM
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Sounds like air in the system. As for the wiring, I would get a hold of a wiring diagram and trace it out yourself.

As for Middle East engineering, "Inshallah". I would try and find a garage run by some ex-pats. Maybe Dubai?
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Old Jan 17, 2018 | 02:28 PM
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Originally Posted by SteveG75
Sounds like air in the system. As for the wiring, I would get a hold of a wiring diagram and trace it out yourself.

As for Middle East engineering, "Inshallah". I would try and find a garage run by some ex-pats. Maybe Dubai?
You are good in Arabic! My friend Muhammad tells me that there are some good mechanics in Sharjah. Actually, I have the car registered there with Sharjah Classic Cars Club.There is also classic cars shop in Dubai so I will try to call them.
Where is the parking brake sensor located, in the cabin or under the car?
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Old Jan 17, 2018 | 02:31 PM
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push switch under the handle in the console
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Old Jan 17, 2018 | 05:31 PM
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Originally Posted by jkrch
You are good in Arabic! My friend Muhammad tells me that there are some good mechanics in Sharjah. Actually, I have the car registered there with Sharjah Classic Cars Club.There is also classic cars shop in Dubai so I will try to call them.
Where is the parking brake sensor located, in the cabin or under the car?
Not good in Arabic but spent enough time in Dubai, Jebel Ali, Bahrain, Kuwait and Iraq to understand the whole "Inshallah" attitude.
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