Couple of questions for the braintrust. Bonus points if you can tie it together into one problem.
Problem #1. I'm wondering if this is a MC, Brake Vacuum, or air in the brake line problem
Volvo brakes (2005 xc70) work- Brakes engage in top 1/3 of brake pedal stroke. Occasionally, no brake engagement in top 1/3- brake pedal unnervingly drops to lower 1/3 of stroke before engaging, at which point it works. (phewwwwww!!!!)
1.Regardless of engagement point, once it engages, it works. The pedal does not "slowly sink" afterwards, like when bleeding brakes.
2. No loss of brake fluid. Fluid relatively changed and ok.
3. If the pedal drops to lower 1/3, quickly releasing and rebraking lets the MC recharge and the pedal engages in upper 1/3 as normal.
4. No sponginess as far as I can tell.
Problem #2. ABS issue.
The code thrown is intermittent- low ABS signal. From what little I can garner, this indicates either a bad ABS pump, or a crapping out ABS computer, the computer especially gets a little complex to fix (remove unit and send to xemodex for reprogramming to new computer.) I do think I am getting 12v to the computer.
1.This goes off, but the ABS system still works. last year I went out and purposely flogged/ engaged/ duke boys the system in snow/ice to try to see what was wrong, but it seems to work fine.
If you can tie these together so addressing the brake issue- say new MC or Vacuum leak fixes the ABS codes (so I don't have to mess with that), I will buy you a pizza or something!
Thanks!
R