Printable View
mine has this.been thinking that it is vacuum related,The first pump the pedal is fine although it feels spongy, The second hardens up a tad because there is not enough vacuum which you compensate for by pressing the pedal harder hence the feeling of a better brake pedal.
Would be interesting to know if it characteristic of both Td5 and V8 engine or is to do with the plumbing on the diesel air pump.
Dunno, it's been six years since I looked. But IIRC they weren't old. Doing the pads and rotors probably tomorrow, when I'm going to follow up on the suggestion that the sliders on the calipers may be seized. Some anecdotal evidence this may be the culprit.Quote:
Originally Posted by trout1105
X2 that - I have a 99 Discovery II Td5 and when my alternator died the replacement was an OEM part that came complete with a new vacuum pump, however when installed there was no change in brake pedal feel compared to the old pump. As is done when ”troubleshooting” brake issues my master cylinder and brake booster pass all the diagnosis tests.Quote:
Originally Posted by lewy
Perhaps vacuum and it’s effect on brake booster performance is dependent on engine RPM because my pedal height and feel has always better at above 2000rpm like when highway cruising but softer and lower in stop start city traffic. I have been meaning to hook a vacuum gauge in vacuum line at the EGR solenoid tee to test but haven’t got around to it yet.
I really do think it's a bleed issue.
My pedal isn't a rock like a Defender, but it's nice and consistent.
Bled the system old school race car style, opened the bleeds at the calipers and just pumped litres of fluid through, no pump and hold, then just for ****s and giggles did a Nanocom power bleed, no difference in pedal feel, then a modulator bleed, then a corner test.
If i think it ever feels a little soft I run a mod bleed and a corner test.
And as a few above have said, a good hit of HDC or go for a blast down a dirt road and hammer the middle/left pedal.
I agree. If the bearings had play or the discs had excessive runout, you would know about it from the shake rattle and roll at the front end. If there is pulsing on braking, look at runout on the rotors ( or bearings ) If there is vibration from the from end through the steering check the bearings.( & balljoints tie rods ) Check the slides as suggested. Also have a look at your pads. If you have gone for a high metal hard pad, the braking can be a lot slower or harder on the pedal until they heat up. Some of the newer ceramic based pads can also have this characteristic. A point on bleeding. Don't be too aggressive in pumping the pedal. Nice slow even pushing. If you stab at the pedal, you can introduce air on aged setups.Quote:
Originally Posted by PhilipA