Mowog73

Member

• Jun 8, 2018

• #1

I'm having an odd brake issue with my 1996 D1 Tdi, which has ABS.

Normally the brakes work find. If you push the pedal really hard, the ABS kicks-in and plusate the brakes. But sometimes, like this morning I pushed the pedal really hard and the brakes didn't lock up, nore did the ABS plusate the brakes. It almost felt like I wasn't going to stop in time. A few kilometres later, I turned in the drive at work and the brakes behaved normally. I am not getting an ABS warning light on the dash. Any ideas what the issue might be?

 

henrytilly

Active Member

• Jun 9, 2018

• #2

you could try bleeding them for a start easy job at little cost worth a go

 

Goc3k

Well-Known Member

• Jun 9, 2018

• #3

If you have poor braking performance and get no lockup / abs pulsation when you need it most I'd check the vacuum pump first, then the booster - as long as you know the system has no leaks / isn't full of air (and that there is some meat left on the pads to boot!)

 

Mowog73

Member

• Jun 10, 2018

• #4

The brakes pads, disks are all relatively new, all calipers are in good working order and the brake fluid was recently changed, so I know that portion of the braking systems is in good working order.

I hadn't thought of the vacuum pump. Is there a way of testing the vacuum pump?

 

Goc3k

Well-Known Member

• Jun 10, 2018

• #5

The easiest test to check the system is, while parked and engine off -

• Pump brakes up until rock hard, hold your foot firmly on the pedal to maintain pressure
• Start the engine - pedal should drop about an inch further fairly quickly.

If the pedal needs two pumps once the engine is running to firm the brakes up, but everything else seems okay, I'd probs suspect the master cylinder next - especially if it is the original unit

 

Mowog73

Member

• Jun 19, 2018

• #6

Thanks, I'll give this a try tonight.