Is anyone aware of published specs on what the pressure should be at the front and rear calipers with full brake pedal application? Has anyone ever tried to measure brake fluid pressure via the bleeder value and a pressure gauge?
brake fluid pressure specs?
Ranger
#2
The OEM repair manual has a test procedure and I think a published spec. The problem is that the spec is, I think, in the “Specifications” appendix, and I don’t have that. I think that Steve Devinney does have it tho. The screenshot below is from the Brakes chapter. It shows a pressure graph for the brake bias valve. Based on the graph 130bar should be do-able in front and 70 rear.
[attachment=2020]BrakePSI.jpg[/attachment]
Steve_D
#3
I emailed Ranger some stuff that might help. He is technical enough to get it posted to FAQ or whatever. Here’s what the book says.
PS - 200 N = 45 pounds of force at the pedal; spec translates to about 900 lbs line pressure. Kinda makes you think twice about using rubber lines that have been subjected to years of heat and abuse, eh?
[attachment=2021]brakepressure.jpg[/attachment]
Matt_H
#5
So what changed after April '87 to make the same pedal pressure equal less line pressure? That must be when the brake master cylinder dimensions changed?
Ranger
#6
Probably different MC bores. http://spece30.com/forum/39-brakes-and-abs/70938-e30-soft-brake-pedal-solved#70940