ST170 Brakes on a Puma

[Jamesgti14]

[post]356113[/post] Weird, I've never even been able to make the ABS work like that. Never experience the ABS working with normal or spirited driving.

Mine kicks in frequently it's very sensitive even hitting a deep drain or pothole whilst braking at 50mph + I hear it grinding and the pedal stiffens.

 

[moondustka]

Doesn't sound right to me.. :?

 

[TGPlayer1]

I've experienced that in a few cars. The sudden change in surface is enough to activate the ABS briefly.

 

[Wild E. Coyote]

It MIGHT have something to do with the fact that master cylinder was not designed to be used with ABS module this way. The ones designed for ABS have onyl two outlets as the ABS pump does the brake distribution

 

[Jamesgti14]

It did it before even with the 258mm discs and original servo.

 

[Wild E. Coyote]

How are your shocks? This sounds like one of them is no good and the wheel keeps bouncing from the road. If a shock is shot (let's assume leaked oil) there is no damping medium and the wheel will bounce off the road. That is easy to spot when driving behind such a vehicle as the wheel is bouncing all the time like a basketball up and down. IF you hit brakes and the wheel is off the ground it will stop right away triggering ABS into action (as a wheel HAS stopped) and that might explain the behaviour you are describing

 

[Jamesgti14]

If anybody does this modification i recomend also making a servo brace to further relieve brake pedal travel. I made one today , just a 3mm thick length of metal with 2 holes cut out (they bolt onto the master cylinder itself) and then a smaller piece of metal welded to the end which bolts onto the ABS pump mounting to the chassis.

 

[Jamesgti14]

Ok so after seeing that the servo moves a lot under braking with new setup , which in turn causes excess pedal travel, so I decided to make a custom bracket to secure it somewhere to the body to relieve the pedal travel. Here it is, it was a quick half hour job doesn't look pretty but I will take it off sometime soon and paint it moondust silver to match the engine bay. I could make more if people like the idea. It has taken up most of the travel now, it now feels almost how I want it to, although I like a bit of travel as it helps with heel and toe braking without you headbutting the dashboard

 

[red]

Forgive my ignorance as I don't know the answer but is it not designed to have that kind of movement? Else why wouldn't they brace it up at build?

 

[moondustka]

No, it's not. Is the simple answer. It has that movement because the mounting and brackets are cheap to produce. It's a compromise between cost and performance.

In cars where there is no brake bar across the bay, that is, the servo mounts directly onto the top of the pedal through the bulk head, the movement is greatly reduced. This also improves response, as there are fewer moving parts.