Brake problem

[Jeff fae Scotland]

Hi guys bit of a weird one here (not me,the brakes) As some as you know on the forum im disabled and use a lever to stop, anyway,this is what is happening.

The lever i use is attached to the brake pedal and when i brake the lever goes down so much to press the brakes on.

What ive noticed is,now and again the travel on the lever is more than normal  and, the car carries on till i push down further.

There is no air in the system as ive tried pumping them. Could it be the brake servo at fault ?? any ideas i would be thankful for...cheers.

 

 

[gazza1286]

This link describes how to test for a faulty brake servo:-

http://www.ukmot.com/MOT test/footbrake.asp

On my 1999 Mk1 Avensis, the issue of soft brake pedal occurred very rarely. But only when the car was being driven slowly and only when the engine was at idle. I never identified the fault but also believed it was linked to a problem with the servo. 

Presumably the linkage on your car has been eliminated as the cause? 

[Jeff fae Scotland]

Hi Gazza,thanx for the reply,Yes the linkage on the lever has been checked.

Forgot to mention,the car is driven by the mrs  and she has noticed it when she presses the foot pedal, but you know what their like

Will have a wee looky at your link thanx again.

[Devon Aygo]

How many miles has the car done ? and is the pedal soft only at lower revs/speeds?

[Jeff fae Scotland]

Cars done 61 thousand miles the pedal seems fine at low revs..

[Konrad C]

Having experienced different brake pedal feeling from different cars over time, I tend associate a hard (wooden) brake pedal to servo failure. I had part of a vacuum pipe break off on a car, leaving the car with no servo! The part was a union joint and the cap was missing. Got replacement from breakers yard the next day. 
Soft pedal after changing brake pads on a car. Also had a soft pedal after changing a wheel cylinder and bled the normal way. Once pressure bled using fairly high pressure, the pedal was firmer. I changed the brake fluid on my previous Avensis, and again pressure bled at high pressure to successfully get a firm pedal. 
With all that info, I think all the brakes should be inspected, making sure the calipers and pads are not sticking, the flexible pipes have not weakened. The brake fluid may need changing as it may have absorbed fluid. Pumping the pedal does not always firm the pedal. 
Master cylinder internal seal failure will show no leaks, but the pedal travel will be longer.
My test of the servo is to press the pedal with the engine off, and when trying to stop the car, the force will be high and pedal travel a little longer. Turn engine on and the pedal will be firmer, less travel and less force needed.
One other thing is that all T27 Mk3 Avensis use vacuum pumps to supply the servo! 

[Jeff fae Scotland]

Well I did what they said in Gazzas link and the pedal never went down any, which seems to point to a leak to the servo...