Dsc and brake pedal, odd question

[thespannerman]

Guys, a bit of a story. Back in June time I was getting the dsc light coming on intermittently, so got two new dsc sensors off eBay. They were very cheap, but seemed to do the trick with no more warning lights coming on. Fast forward to a couple of weeks back and I get the dsc light on again, this time all the while. But I hadn’t thrown away the original sensors, so refitted those and dsc light is off, but occasionally comes on. I order two (hopefully) better quality sensors and fit them yesterday. No warning lights now on, but the strange thing is that the brake pedal now seems to “bight” about an inch lower in the travel than it did before. I sealed the master cylinder before swapping the sensors, and lost very little brake fluid when changing the sensors. There are no leaks anywhere and the brakes work fine, no sponginess, so can’t understand why the pedal is now different.

Ideas ????

Al

 

[Ewazix]

I think you need to eliminate the possibility of air in the lines, I'd replace and bleed fluid including activating the ABS unit if you can.

Once that's done start checking booster vacuum pipes and hoses, maybe something got disturbed?

 

[thespannerman]

It’s there a sequence to bleeding the brakes, do you start with the wheel furthest away from the master cylinder.

Al

 

[colb]

Yes so thats going to be the rear with the longest run from the master cylinder followed by the other rear then onto the front with the longest run from the master cylinder and end with the remaining front thats got the shortest run from the master cylinder. Keep the master cylinder topped up when bleeding do not let it fall too low so air gets into the system. If you do then it will require the ABS being activated to clear any air that has got into it. You would have to go around and rebleed all four again.

 

[thespannerman]

Ok cheers. On a uk car I guess the longest run would be the passenger side rear first, then driver’s side rear, followed by passenger side front then drivers side front.

Al

 

[patriot66]

Ok cheers. On a uk car I guess the longest run would be the passenger side rear first, then driver’s side rear, followed by passenger side front then drivers side front.

Al

Actually, the longest brake line run on a UK E85 is to the drivers side rear brake as it runs alongside the nearside brake line (underneath the plastic underfloor weather panel)to the rear and then up and across under the boot floor to the drivers side rear arch, so I always start with that caliper when bleeding

 

[thespannerman]

Ok thanks for that, cheers

Al

 

[DMike]

I’ve also been bleeding my brakes as described above. Last time when clearing the service interval I noticed there’s a specific ISTA routine for brake bleeding. Youtube videos show how to use ISTA for this and that included activating DSC/ABS. I’ve also had intermittent DSC sensor errors for years (just a couple of times and they’ve cleared with cleaning the connectors). Probably wouldn’t hurt to start doing ISTA and DSC bleeding routinely?

 

[thespannerman]

Just got round to doing the brake bleed, and it’s fixed my problem. Looks like it was some air in the front passenger side pipe, all the others were ok.

Happy now

Al