Hey everyone. What would be the indications to turn or resurface rotors? My truck takes a long time to stop sometimes and it is to the point where I am nearly blowing red lights. The brakes stop fine on flat surfaces, but in certain conditions it takes alot longer (Like stopping on a hill) and sometimes it doesn't want to hold on a hill (Then I have to put it in park). I have already had them checked so many times and noone can find any problems with them. The pads are fine and can last another 10-20k miles. The pedal travel is fine, consistant and doesn't go to the floor. Most of the brake system was replaced 2 years ago. But I notice that all of the rotors are dark and marked up big time because they get alot of heavy use. Last time anything was touched was in December when the passenger side wheel bearing was replaced. No idea if the left one is bad (only a year old), but that is a different matter. Only one shop in this little college town CAN remove them and send them out to turn them, the rest only want to replace them. My mother back home goes through rotors alot (Toyota) but was able to get them turned 2 or 3 times before they were thin enough to have to replace. Should I have these rotors turned?

 

1st off I'd bleed the brakes starting with the rear PS then the rear DS & front PS. Furthest away from the master brake cylinder & working back.
Look for obvious signs of scoring, gouging on the rotors - all 4 corners.
Depending on the shop they may be able to turn the rotors & resurface them. I'd also look for vacuum leaks & make sure the fluid is topped up especially the vacuum if the brakes work better when you pump them & bleed them as I mentioned. Looking at the rotors & bleeding them is free as well as spraying brake cleaner over vacuum lines to check for leaks.. well almost, maybe $4 for a can of brake cleaner. If it revs higher or different when you spray brake cleaner over a line - you've found a leak!

 

Thanks for your quick response

Brakes were bled several times in the past 2 years after major work was done on the system after a major malfunction. I would say in the double digits. No mechanic I have spoken to thinks it is necessary and refuses to do it. They think they would be able to feel if there is air in the system. Fluid is full and has never leaked.

There is a vac leak somewhere, but it doesn't affect the engine itself. It idles perfectly at 550. The only real noticeable issue is the HVAC actuators at higher engine speed. I thought the intake manifold was leaking, but that is on another thread and it is only the RTV sealant instead of the lower intake gasket. I replaced all hoses already and bypassed the one to the transfer case.

Through all of this, we can say the vacuum and hydraulic parts of the brake system is fine. That leaves the mechanical parts.


There are some score marks on all rotors in addition to the scratches, color and rust.

 

Scored rotors will just eat your pads fast, think you need to find the vac leak before you kiss a tailpipe.

 

Your vacuum line for the HVAC may run into the DS fenderwell & into a box, then it runs into the cab & the HVAC controls. That line runs past the brake booster & may be tee'd into the booster. If you have a leak with the HVAC then it also could affect the brake booster. I'd look into the lines that run to the fenderwell & from there into the cab & under the dash. Hopefully the leak is under the dash & not in the fenderwell, that one is a PITA to get to, I think I have to remove the fenderwell liner above the tire to get to it.

 

It is connected to a vacuum tank. It isn't tee'd into the booster. The one for the booster is a wider hose connected to a different location. I replaced all the smaller hoses. Is there a way to replace the vacuum tank with an "orb" that is on the older trucks?

 

No idea about the 'orb' but a vacuum leak is a vacuum leak. Your vacuum comes from one place - the engine, so if another line has a leak the overall vacuum will probably be less.

 

The leak only surfaces at higher RPM (around 1800-2000). Which parts of the engine are providing the vacuum? Is it the plastic (why, oh why, do they use plastic on something that has to be reliable?) upper part or the metal lower part? If the hoses are new and if the lines under the dash are fine (I will check them out, but last time I had the panels off everything was fine). Could the RTV sealant on the lower intake manifold be at fault? I found some of the RTV pulled out and some bubbles, but I can see the hard gasket and it doesn't appear breached.

 

2000rpm isn't what I'd call higher rpms, that's city cruising rpm or highway in OD. That being said the engine is making more vacuum than at idle & it has a leak that's effecting vacuum operating componants. Trace the tubes back to the engine & see where they hook into. Then you'll know if the manifolds gasket could be the culprit. If you see bubbles of something (coolant probably) then rip it apart, clean the surfaces & replace the gasket properly.
Personally if I saw a leak or bubbles on any gasket I'd tear into it or at least consider that as an issue for a vacuum leak but replace that gasket because it's just not doing what it was designed to do - seal!