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Registered:
June 2003
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MA61 brake problems
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Mon, 14 June 2004 04:43
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LONG POST - here goes
I have an MA61 wih a 7m-gte convsersion. I'm getting a strange problem with my brakes now, which I believe is a vacuum hose off somewhere.
Here's basically what happens:
If I apply the brakes slowly and evenly, I get perfectly normal braking.
If I jump on the brakes REALLY quickly (in the case of emergency braking, for example), nothing happens. The brake is almost impossibly hard to press down - it's the same as when you turn the engine off and press the brake pedal a few times. It gets REALLY hard to press down, as if the power assisted braking is doing nothing at all.
I don't quite understand why though, because I can feel the power assisted braking working perfectly if I apply the brake pedal slowly. It's only if I stomp on it that it doesn't work.
I believe I have found the vacuum hose causing the problems, but I don't know where it should be going. I've attached some piks below with the hose in question. Does anyone know where this hose is supposed to go to? I can see it's coming off the brakes, but I need to know where it goes to. Ideally, if someone could also give me a vacuum hose diagram for the MA61 and the 7M-GTE that'd be great.
At the moment, the hose in question taps off the brake pressure/vacuum line and runs off along the firewall.
The little mini vacuum diagram under the bonnet isn't even remotely useful, and the Haynes workshop manual doesn't go into enough detail either.
Help please - I'm scared of driving in case I have to jump on the brakes!
-J-
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: MA61 brake problems
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Mon, 14 June 2004 04:48
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| joorsh wrote on Mon, 14 June 2004 12:43 |
it's the same as when you turn the engine off and press the brake pedal a few times. It gets REALLY hard to press down, as if the power assisted braking is doing nothing at all.
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Thats perfectly normal.
As for the hose, there shouldnt be anything Teeing off the brake vacuum hose.
It should go straight from the manifold to the booster.
That other little unit, the charcoal canister is supposed to be connected to one of the outlets above the throttle body, not off the brake booster line
Remove the T and see how she goes.
Oh, and bleed your brakes too.
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Mon, 14 June 2004 04:54
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If you start your car with your foot on the brake pedal does it depress? It should.
Also isn't there meant to be a one way valve going to the brake booster (can't see if yours is there..)
Cheers
Wilbo
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: MA61 brake problems
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Mon, 14 June 2004 04:57
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| wilbo666 wrote on Mon, 14 June 2004 12:54 |
Also isn't there meant to be a one way valve going to the brake booster (can't see if yours is there..)
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Good point Wilbo, yes, yes there should be
That could be your problem.
I'd say they removed it to put in that T piece
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Registered:
June 2003
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Re: MA61 brake problems
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Mon, 14 June 2004 05:58
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I know that the brakes are supposed to be difficult to press down with the engine off - I was just giving that as an example of what my brake feels like when I stomp on it - as for the tee-piece, it is currently blocked off and goes nowhere. I have also tried removing the tee-piece and running it direct to the booster - still no luck.
And that IS the booster than it runs off to - that little vacuum line running along the back of the firewall goes from the brake manifold to the booster?
And something about a one-way valve? Does anyone have a pik of it? Or even a dodgy mspaint sketch will do!
-J-
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: MA61 brake problems
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Mon, 14 June 2004 06:29
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Little white/yellow thing at very top of pic.
In the line
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Mon, 14 June 2004 06:33
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| joorsh wrote on Mon, 14 June 2004 15:58 |
I know that the brakes are supposed to be difficult to press down with the engine off - I was just giving that as an example of what my brake feels like when I stomp on it
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I was curious as to if the brake pedal goes down further when you start the car with you foot on the brake pedal (this is a test to see if the brake booster is working).
One way valve..stolen from CrUZsida, site, so kudos to him.
See the little white thing in series with the hose? Thats the one one valve 
EDIT: dammit you bitch you beat me too it! 
Cheers
Wilbo
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I supported Toymods
Location:
Australia
Registered:
November 2003
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Re: MA61 brake problems
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Mon, 14 June 2004 07:12
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| wilbo666 wrote on Mon, 14 June 2004 14:33 |
EDIT: dammit you bitch you beat me too it!
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'course I did
I got a better picture too!!
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Mon, 14 June 2004 07:38
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bite my hairy ass 
Cheers
Wilbo
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Registered:
June 2003
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Re: MA61 brake problems
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Mon, 14 June 2004 12:02
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Why does mine look totally different? I have a metal rail at the back there, whereas you all seem to have a hose. Could my rail incorperate the one way valve already?
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Mon, 14 June 2004 12:45
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Try blowing/sucking through it?
You should be able to suck air in from the end that connects to the booster but not blow.
Cheers
Wilbo
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Mon, 14 June 2004 12:47
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Those guys posted photos of an MX73 Cressida, which isn't terribly helpful in this case. The line you've tee'd into looks like the cruise control actuator line, although that's just going from memory. The one-way valve is much closer to the booster on an MA61, and it looks different to that. If it wasn't cold and dark outside I'd go and have a look at mine, but instead I'll just sit here and speculate.
Anyway, the symptoms you describe kinda sounds like a punctured booster diaphragm. It's worth checking out.
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Registered:
August 2002
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Re: MA61 brake problems
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Mon, 14 June 2004 12:58
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Hving arsed around all day in that particular section of the engine bay im pretty sure i have 1 line going to my now removed cruise control servo/actuator and another to a carbon canister.
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Tue, 15 June 2004 12:30
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I think its the little metal thing behind the maser and above the brake booster (hehe cheers jemery )
And mine is on the firewall (ahh look at the turd)..
Cheers
Wilbo
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Location:
Brisbane
Registered:
May 2002
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Re: MA61 brake problems
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Tue, 15 June 2004 22:46
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Stop posting pics of 5M-E's. It hurts my eyes!
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Location:
Adelaide
Registered:
June 2002
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Re: MA61 brake problems
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Wed, 16 June 2004 12:42
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| Norbie wrote on Mon, 14 June 2004 22:17 |
The line you've tee'd into looks like the cruise control actuator line
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Indeed it is the cruise actuator line.
I'm curious as to why there is such a mess of hoses there? It's no wonder something isn't right!
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: MA61 brake problems
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Wed, 16 June 2004 13:47
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well the 2 big fat ones are for the remote oil kit
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