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Old 25th June 2010, 15:31   #1
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Default Indica Vista saffire brake problem when AC is on

Hi all
Brakes of the Indica Vista Sapphire become hard when Air Condition is ON.
When driving in traffic driver cannot drive car using half clutch as brakes become hard and it become difficult to stop the car(this problem is observed when AC is ON).

Could someone pls tell me how I can get this rectified ?

Thanks
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Old 25th June 2010, 16:08   #2
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when you say the brakes are hard..
do you have to put extra pressure on the pedal to stop the car?
or do u have difficulty in pressing the brake pedal?

an extra note..
when your car is standing still and when you switch on your AC does engine idle increase very slightly?
please mention the RPM of the engine idle when AC is 'on' and 'off' at idle only.

cheers
Saud
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Old 25th June 2010, 16:32   #3
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Pls check all the Pulley belts tension - Have a mechanic do that.
Pls check the Alternator/Battery Voltage. Is the Alternator charging, is the battery charged.
Pls check if the Idle RPM with AC on is about 200 higher than with AC off.
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Old 25th June 2010, 16:46   #4
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the breaks become hard, as if the car brakes are pressed when the vehicle is off. pressing further may not be of any help .

I have not observed the RPM meter b/w AC on and off. Might be there is an increase in rpm. This problem does not apprear immediately after the vehicle started, if we run the vehicle with AC on and at slow speed for some time, may be for 5-10 minutes, we can experience this. How do I procede ?




Quote:
Originally Posted by msaudf View Post
when you say the brakes are hard..
do you have to put extra pressure on the pedal to stop the car?
or do u have difficulty in pressing the brake pedal?

an extra note..
when your car is standing still and when you switch on your AC does engine idle increase very slightly?
please mention the RPM of the engine idle when AC is 'on' and 'off' at idle only.

cheers
Saud
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Old 25th June 2010, 17:01   #5
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Like ACM suggested, check your belts. The problem your car is showing maybe because of lack of vacuum pressure to the brake master cylinder.
are you sure the problem disappears when the AC is off?
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Old 28th June 2010, 15:51   #6
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@ACM, @MSAUDF, I will get the belts tension, Alternator voltage etc. I think the Battery / Alternator is doing well, there is no issue with the charging of the battery.

The issue disappears when the AC is switched off, or switch off the vehicle and restart. but switching off the AC is better option. Thank you all, Will post the results once I take it to my mechanic.
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Old 29th June 2010, 03:44   #7
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Hey, I think when the A/C is switched on, the engine power gets diverted to the A/C and there is less power to create the required hydraulic pressure for braking. Now, I'm not quite familiar with Indica's bets or how the above procedure occurs in Indica, but this may be a reason. Experts, please advise.
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Old 29th June 2010, 20:41   #8
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Quote:
Originally Posted by high_octane View Post
The issue disappears when the AC is switched off, or switch off the vehicle and restart. but switching off the AC is better option. Thank you all, Will post the results once I take it to my mechanic.
Am not familiar with the particular model, but if it is like any other petrol vehicle, the vacuum for the brake booster will come from the inlet manifold, and not from a separate pump.

When the AC is switched on, rpm is increased, reducing the vacuum, and therefore the brake boost. Also you are now braking against an engine which is effectively turning faster. Both of these will mean more braking effort. Normally the rpm increase due to braking should not matter much, but I would suggest your mech checks out manifold vacuum and idle rpm with AC on and off, and check it against specs.

Switching the vehicle on and off should not make a difference, so can't explain it, unless this model has a AC delayed turn on feature.

Regards
Sutripta
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Old 29th June 2010, 20:59   #9
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Get vacuum lines leading to the brake booster/master cylinder checked. This is not normal.
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Old 2nd July 2010, 21:59   #10
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The hose connecting the ECU and vaccuum cylinder. It has something to do with the Ecu because the ECU should be able to produce same strength of vacuum boost with AC on. Some Indicas have this hereditary problem.
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