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#1
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Front rotor thickness
I have to put new pads on the front brakes of my '85 300D. While I am there I would like to check the rotor thickness. Can anyone tell me what the spec is regarding the rotors? For that matter, what is the spec on the back rotors?
Thanks.
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Charlie --------------------------- '66 VW 1300 96K miles '97 E300D 239K miles '85 300D 203K miles (sold Sep 2012) |
#2
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that info should be found on the rotors stamped into the steel. it may or may not be legible depending on the amount of rust
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1967 250 S 1967 280SE 1968 250S 1971 280 SE 1973 220 1974 280 S 1975 450 SEL 1976 220 D 1979 300SD 1983 300 SD 1985 230 TE euro 1986 280SL 1986 500 SEL euro 1986 190E 2.3 1990 300 SE 2003 C230 K 2004 C230 K 1987 560SEL 1987 300SDL now in canada 2005 C230 1998 C43 AMG Sold to DON 1993 190E 2.6 300TD Former daily driver Totaled current: R320 CDI Ram 2500 Cummins |
#3
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The rotors on the w123 are designed to be replaced with the pads.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
#4
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Thats interesting. I think every other pad replacement works
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http://superturbodiesel.com/images/sig.04.10.jpg 1995 E420 Schwarz 1995 E300 Weiss #1987 300D Sturmmachine #1991 300D Nearly Perfect #1994 E320 Cabriolet #1995 E320 Touring #1985 300D Sedan OBK #42 |
#5
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only if they are below minimum thickness,
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1967 250 S 1967 280SE 1968 250S 1971 280 SE 1973 220 1974 280 S 1975 450 SEL 1976 220 D 1979 300SD 1983 300 SD 1985 230 TE euro 1986 280SL 1986 500 SEL euro 1986 190E 2.3 1990 300 SE 2003 C230 K 2004 C230 K 1987 560SEL 1987 300SDL now in canada 2005 C230 1998 C43 AMG Sold to DON 1993 190E 2.6 300TD Former daily driver Totaled current: R320 CDI Ram 2500 Cummins |
#6
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All the stuff I read here, shows the rotors should be replaced with the pads. I think it's silly also, and down right pathetic that the 123 got solid instead of vented rotors. Mine are warped, but not below min thickness. Turning them would put them at minimum thickness, and the danged bolts that mount the rotor to the hub have a ton of blue loc-tite on them.
That would explain why I could not get them loose. Here at the shop, since I am buying new rotors, we are going to lathe off the rotor so we can get a decent 10 mm allen in there, and heat up the hub a bit to release the loc-tite.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
#7
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Rubbish.
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#8
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If it's rubbish, then cool, less expense for me! I like being proven wrong when it saves money!
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
#9
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Disc thickness, how thin can you go?
From Haynes manual, brake rotor F 10.6mm (0.418in) R 8.3mm (0.327in). If they measure, no need to replace. Also I've heard they are not to be turned, as that can lead to serious problems with caliper pistons pushing beyond they're travel limit. But you won't know that untill the pads wear down to the point of no return.
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83 SD 84 CD |
#10
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Which is one of the reasons for a minimum thickness specification.
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#11
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Thanks to all for the answers so far. I didn't know the Haynes had the specs - I would have looked it up myself. I have a micrometer so I can measure the rotors at various places along the edge. If I'm lucky my rotors are OK.
I believe that rotor removal on a W123 requires disassembly of the hub. Question - when I put the wheel back together, I have to set the end play of that nut that holds everything on. This is best done with a dial end play gauge. Where do I get one? The auto parts store here didn't have one. Or is the Haynes' manual procedure sufficient, where they tighten the nut until the rotor won't turn, then back off 1/3 turn?
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Charlie --------------------------- '66 VW 1300 96K miles '97 E300D 239K miles '85 300D 203K miles (sold Sep 2012) |
#12
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This will work. Or, tighten tight, with channel locks, back off till the channel locks "break free", then tighten 10 degrees. You may want to get a feel for it when you remove, also note the oreintation, might help. When you're in there, repack wheel bearings. There is a grease seal that should be replaced, inside bearing, as you will damage when removing. New sensors also, if so inclined. The thickness info is on the opening page to the brake section. Capter nine, page 162, in my manual. I had to look in chapter one to find the 1/3 turn thing.
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83 SD 84 CD |
#13
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Thanks, that answers my questions for now. The front hub assembly/lube thing is remarkably similar to my old VW. Interestingly, VW gave the front left hub reverse threads for the locking nut, which doesn't seem to be the case here.
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Charlie --------------------------- '66 VW 1300 96K miles '97 E300D 239K miles '85 300D 203K miles (sold Sep 2012) |
#14
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FSM section 33-300 "Adjustment of wheel bearing and play"
Wheel bearing end play 0.01 - 0.02 mm Tighten clamping nut while simultaneously rotating hub in such a manner that hub can be turned with considerable force only. Then screw clamping nut back approx. 1/3 turn and release tension by applying a blow with a plastic hammer against wheel spindle. Place test instrument (Dial indicator) on front wheel hub and set dial gauge to approx. 2mm preload. (Magnetic base goes on upper part of rotor where the lug bolts screw into). Check end play of wheel hub by pushing and pulling on flange. Rotate wheel hub several times prior to each measurement. WHILE MEASURING MAKE SURE WHEEL HUB IS NOT ROTATING. ACCURATE END PLAY READINGS WILL NOT BE POSSIBLE. Tighten hex socket screw on clamping nut and check end play again. If all is well put it back together in the reverse order of removal. Danny
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1984 300SD Turbo Diesel 150,000 miles OBK member #23 (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination Last edited by dannym; 04-17-2007 at 12:54 PM. |
#15
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I have to do my bearings as well. I do not have a dial indicator, and do not have the bucks to get a good one. I'll do everything except the dial indicator part.
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RRGrassi 70's Southern Pacific #5608 Fairmont A-4 MOW car 13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete. 91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K 90 Dodge D250 5.9 Cummins/5 speed. 400K |
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