vze2jshn

While searching for new replacements it seems both front and rear rotors for '78 are the same. Correct? Also, can I replace with 2 rotors on one axle from mfg. Sebro and 2 from Zimmermann on the other axle?

James Bailey

correct they are not directional....yes you can use different rotors on different axles just as you can mismatch brake pads with little real difference.

GregBBRD

Interesting wording. I'll answer the first question like you wrote it.......Front and rear rotors are completely different. They are, as Jim said, intechangeable right to left.

Different cast iron materials have different coefficients of friction....I've learned this lesson several times in my lifetime. While I would never mix brands of rotors side to side....it's probably going to be difficult to know front to rear.

Rob Edwards

'78 front rotors are 928 351 041 09, rears are 944 352 041 02.

waynestrutt

While searching for new replacements it seems both front and rear rotors for '78 are the same.

If the front and rear rotors are the same how does your park brake function?

Rob Edwards

Whatever you were reading is incorrect. You're right, the rear rotor hat is 10 mm taller to accomodate the parking brake pads- 50 mm vs 40 mm.

Rotor thickness is 20 mm, front and rear.

FWIW, for '78-81, the rear rotors are actually bigger than the fronts- front on the left, 281 mm vs. rear on the right, 288 mm:

James Bailey

Both FRONTS are the same, both rears are the same BUT fronts and rears are NOT the same as Rob has so clearly pointed out and Greg alluded to as to how oddly the OP was worded..... The reference to using different brands of front with different brands of rears implied that he was aware that all four rotors were not the same and was considering mismatching brands. Which is probably not a big deal !!

vze2jshn

Thanks for clarification gents. I was confused by the fact that 1 or 2 web sites would list only rear rotors when I would search for fronts. I also noticed that the rotors currently on the front of the car are slotted-- I had replaced them many years ago and it seems slotted rotors have right and left designations and I had been sent and installed two of the same which I had not noticed until I had a few years and miles on them. Original front rotors waaay back, If I remember correctly, were not slotted.

Rear rotors (not slotted) were replaced even farther back and I don't currently have the rotors off the car yet so I did not notice the obvious differences between front and rear. Neither fronts and rears have been machined but are at thickness limits as if machined - I miced them while still on the car with the calipers off. Calipers need to be rebuilt, seals on all four are dried out and torn.

I have a good source for Sebro or Zimmermann for rears with excellent pricing. Has anyone had any experience with EBC Premium rotors or Ocquence rotors? (I've never heard of them till now while searching) Any guidance regarding mfgs is greatly appreciated.