View Full Version : brake question

09-17-2005, 04:30 PM
1999 gmc safari can the rotors and drums be turned. or do u have to replace every time. Midas muffler is telling my sister inlaw that u
cannot turn either, no matter how light the grooves are. any truth
to this??? or are they just out 2 lunch? What ever happened to
having them turnned.

09-17-2005, 06:58 PM
Its honestly better to just buy new ones unless you absolutely cannot afford it.

If they are telling you they can't turn the rotors or drums, ask what the measurements are, and ask to see the max allowable on the drum/rotor. It also depends on the style of mount, they may not have the peice for your hub.

The drum is measured with a drum guage, the Rotors usually with venier calipers.

Call Napa or Lordco, and ask for specs and if they turn them. Then atleast you have the specs and know if they are lying to you when you go in.

77 K5 - Big, black, ugly and all mine :)
`Erotic, Exotic, and a lil'Psychotic`

09-18-2005, 05:17 AM
There is minimum machine thickness for the rotors, and maximum machine diameter for the drums. Unless you've gone metal to metal G.M.'s are usualy pretty good at not needing replacement. If however you do have to replace them, only use quality parts, GM or the best after market. I just recently bought a 97 Yukon from a dealer. It had a brake pulsation, so rather than machine the perfectly useable parts they put on new ones. After they did the truck stopped like shit, so I went to there srap bin, got my old rotors, machined them and put them on. The trucks braking ability almost doubled with no other changes oth than the rotors. The rotors they put on cost $34. , when i looked into it, I found that quality rotors were $190 and GM rotors were $230. So it seems is what is happening is because of labour costs as compared to cheep rotors shops are now just putting crap on vehicles cause its cheeper than machining.

09-18-2005, 08:02 AM
thanks for the info I will let her know, any suggestions on a good shop in langley she could go to?

09-18-2005, 08:49 AM
Cast rotors with a stamped-steel center do not machine well. The bi-metal composition causes a harmonic vibration when machining and the rotor will not machine smooth. I didn't believe it until I tried it.

IMO, there is nothing wrong with small grooves in a rotor - but Midas may have their own rules about lifetime warranty pads and such so they have you over a barrel there.

I recommend Visscher's Auto Repair (Cloverdale) for a decent shop.

09-18-2005, 09:07 AM
You have to have the proper adapters to machine the composite rotors, I can machine them perfect every time.