It keeps going soft...

[Ben Willis]

I have VX HPC with standard brakes which spends most of its life on the road. On its occasional track days after a few laps the pedal goes very soft. The car still stops okay after what feels like a mile of pedal travel (so I am not suffering from fade? It may be a bit worse, it is hard to tell). Pumping the pedal makes no real difference but after everything has cooled down on the drive home, they seem to go back to normal.

 

I got the problem last year and took it to Hyperion who changed the fluid (presumably to 5.1?) and the pads to “suitable road/track compound” from the Greenstuff that I had (which they said had cracked very badly). This was fine on the road and better but still not great on the track.

 

Hyperion told me they have race cars running fine on standard brakes, but I am not imagining it – they definitely go soft. So will Caterham’s big front brake kit help or not? What about James Whiting’s conversion? Or is there something else? I didn’t bleed them immediately before the trackday but it is only about 2 months since Hyperion last did them so I can’t imagine it is that.

 

If I don’t hear otherwise I guess I will save up for the big brake kit, but I get the impression that helps with fade which I don’t think is my problem. Any help greatly appreciated before I spend more money on the wrong thing.

 

Ben

[EFA]

Ben,

 

Caterham big brake kit is the way to go. The std front brakes are not up to stopping a Seven repeatedly from the kind of speeds a VX car can achieve. I had a huge accident on std front brakes on a VX HPC.

 

I would recommend you try either Red Stuff (which seems pretty durable on the road (and believe me I drive hard....) or Mintex 1144 compund all round.

 

I also run AP600 fluid which has a much higher boiling point than any other fluid so the risk of vapour lock is reduced. If you use AP600 though, you should ensure you change it every 6 months as it is more hydroscopic than normal fluid.

 

 

 

 

 

 

 

Fat Arn

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[Ben Willis]

Arnie,

 

Thanks for that. I have heard rumours that going to the big fronts might mean I'll need a race master cylinder, and then a proportioning valve to stop the rear locking and then....

 

I don't want to buy the fronts and then drive round with a dodgy setup while I try to save up for all the other bits I really needed to get at the same time.

 

Can you fit just the front brakes without all the other stuff?

[Mike Bees]

Yes you can.

 

Fitter bigger brakes to the front won't make the back ones start locking... In fact in my experience with the big brakes on the front and standard ones on the back the bias is too much to the front (i.e. fronts lock way before rears).

 

Mike