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Discussion Starter #1
Hi guys,

I hope you can help!

The car is a 67 Giulia Super with a Bendix Servo.

When i first purchased the car, the brakes worked fairly well but in the last 12mths the pedal effort required has increased alot. I've tried the following to work out what the problem could be:

I tried pushing the brake pedal at idle to see if the revs would change as i believe this is indicative of a faulty servo, no variation in revs was observed.

I visually inspected the brake rotors and found that both the rear rotors had a fair bit of rust or rather rust colouring unlike the front discs. In the last 2 weeks I've probably travelled 150kms and would have expected the rotors to be clean.Could this mean my rear calipers have fozen? BTW when braking the car stops in a straight line without pulling to either side.

I would love your thoughts, opinions and suggestions to my problem.

I've attached a picture of my car to assist ;)

Thanks!

Luis
 

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If the pedal effort is getting higher it probably means the booster is on the way out.

You might check to make sure your pads are thick enough. As they get thin, they hit the pad retaining clips before clamping properly on the disks.

Disk, especially rears, can remain dark and mottled looking even when working OK. But you might check with one person pushing on the pedal, and you spinning each wheel, to make sure each corner's brake is functioning properly.

Andrew
 

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I'm with Andrew here. The rev-test isn't the only way to determine if a servo is failing or has failed. It shows if there's a loss in vacuum, which the servo would introduce if the rubber is punctured somewhere. But as far as I understand how these work, if the booster valve is stuck closed you'd have no brake assist *and* no loss in vacuum. Just a theory, but that's where I'd look.

Aaron

ps: beautiful car!
 

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Welcome to the AlfaBB, 67Super.

...I tried pushing the brake pedal at idle to see if the revs would change as i believe this is indicative of a faulty servo, no variation in revs was observed.
Actually, it's the other way round. On a system that is functioning properly, pumping the brake pedal causes the servo to 'use' vacuum. Since the vacuum source is the #4 cylinder, this vacuum use will lean the mixture to #4 cylinder and cause an RPM change.
I'd check first to see if there is vacuum at the servo. Disconnect the hose at the servo, start the engine and feel if there's any vacuum in the hose.
 

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Discussion Starter #6
Wow! Thanks for the great response and info guys.

I'll do some further testing tonight using your suggestions and let you know how I go. In the event that it is the booster, whats the best course of action? Repair kit? Recon unit? Cost? etc

Alfatogo, the Super has its original 1600 engine which has been upgraded with electronic ignition but otherwise I think it's stock as a rock. Great fun to drive! I'll post some more photos over the next couple of weeks.

Thanks

Luis
 

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Discussion Starter #7
Hi Jim

I thought I would have a go at trying your suggestion tonight.

I disconnected the servo hose that runs to the engine at the servo and started the car. I observed that the hose was sucking. I then pressed my finger against the servo nipple where the hose had been attached and felt nothing. Was I suppose to feel something? Unfortunately I'm home alone tonight so I couldn't get someone to hit the brakes while performing this test. That will have to wait until the weekend unfortunately.

Thanks

Luis
 

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The hose, when attached to the intake manifold, should be pulling a vacuum and suck your finger in. The fitting on the booster, when disconnected from the hose, is at ambient pressure and will neither suck in nor blow out. That is, there is no separate vacuum in the booster; it gets its vacuum from the hose to the intake manifold.

Andrew
 

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Could try this -run engine switch off push brake down 1...2...3....4 times does it get harder to press or the same. Then start engine with foot on brake as engine starts does it drop down, if not no booster(probably)
 

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Discussion Starter #10
Hi guys,
I've had the flu this weekend so I've only been able to complete 1 additional test. With the car off, I pumped the brake pedal 5 times, keeping my foot on the pedal the fifth time and then started the car. The pedal feel or effort did not change. To make sure I reperformed the test again straight after with the same result.

To confirm my understanding, this mean the booster is ineffective?

Thanks

Luis
 

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I think the booster is gone then. Especially if it stops normally except for pedal effort. Beautiful car you have there, well worth speding money on the brakes!
 
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