Brake upgrade for early model W124 - Page 2 - PeachParts Mercedes-Benz Forum

omegabenz · #16 02-12-2003, 12:26 PM

my view on 400E rear brakes. The caliper is the same as 300E ones except there is a spacer inbetween them to allow for the extra thickness of the vented rotor. The vented rotor is good, but having to mess with the dust shield isnt worth the upgrade, when you can go to 500E or SL500 or Sl600 brakes, which all of these 400e/500E and the SL R129 all have the same rear dust sheild. For your 190E if you like cutting dust sheilds, I would say that would make you have plenty of brakes...My friend has a set of 400E rear brakes if someone is interested, I could even take the dust sheild off too.

gsxr · #17 02-12-2003, 12:38 PM

Minor correction. The late model E320 (1993-95) did indeed have the same diameter rear rotor (278mm) as the 400E/500E, but with solid (9mm) discs intstead of vented (24mm). However the early 124's (1986-92, approximately, and ALL diesels) had smaller 258x9 rear rotors - except the 1990-up coupe, which got the 278x9's.

Basically any 24-valve engine got bigger brakes (front and rear). The brake size from the factory was directly related to engine power output, that's why the 93-up E320 got the upgrade, because power jumped from ~177hp to something like 217hp. The coupe had the M104 engine before the sedan, hence the different year for the brake up-sizing. The ONLY cars that had vented rear rotors were the M119-powered models - 400E/500E.

Confused yet?

omegabenz · #18 02-12-2003, 12:41 PM

Im not confused one bid dave. =) M104 CIS or fuel inject cars, which brakes...different ones...haha.

Cardude · #19 02-12-2003, 07:13 PM

GSXR: And my E320T, has vented rear disks!

Cardude

gsxr · #20 02-12-2003, 07:31 PM

Cardude... you're correct! I purposely left those off the spreadsheet, as only 1993 through mid-1995 wagon models (124.092) had them. There are a few other non-US models that used these as well. They are 278mm diameter, but a little thinner at 20mm instead of 24mm. I figured they were rare enough that it would just cause more confusion.

Late 1995 wagons got larger diameter (290mm) but non-vented (10mm) rotors.

And finally, to add the last thing not on the spreadsheet (I think), the 1993-94 500E shipped to the rest of the world (everywhere EXCEPT the USA and Japan) got huge 300mm x 22mm rear brakes, from the SL600 I believe. I think you need the SL rear hub to make that work on 6-cyl 124's, though (but it should be a bolt-on to a US-model 500E.)

:p

HTH,

gsxr · #21 02-27-2004, 10:14 PM

I finally got a round tuit and started messing with my E420 brake upgrade. Someone on the MBshop forum tried this and said the bigger front rotor hit the lower control arm, d'oh. But Rick (2phast) had no problems with his 190E, so I figured it was worth a gamble. Anyway, they don't fit - yet. With the stock font rotors, there is about 3mm air gap to the splash shield, and another 3mm from the back side of the shield to the ball joint / LCA (lower control arm). The problem is, the bigger front rotors are 6mm deeper! Translation - no air gap, no fittee. If the shield was removed entirely, the rotor would probably be 1-2mm from the LCA, way too close IMO.

There are a couple solutions. The obvious method is to use the correct, late model LCA designed for the bigger rotors. The bad part is they're ~$100/pair used, plus another $100+ for new Sportline LCA bushings, and - get this - the BJ is not replaceable! It's welded in place. IF the BJ goes bad, you have to buy another control arm! They're $250/ea new wholesale, ouch. Translation - ~$525 for new ones, or ~$225 used with new bushings. OUCH.

Another option is to swap the 500E/R129 hub, knuckle, and steering arm. I'm not sure if this will work with the 294mm rotors I currently have, but it will work with either the 300mm or the 320mm rotors from the 500E/R129. Since I don't have any of that stuff and it's not cheap to get new OR used, I'm scratching that idea. It would be ok if you can get the bigger stuff to begin with, but I didn't, oh well.

The 278mm rears are fine - they will bolt up with zero problems once the splash shield is cut or replaced. Austin says the bigger 300mm rears used on the SL600 and most later AMG models also bolt up, using the SL600 rear rotor. Sooooo, I'll probably end up getting used front LCA's, hoping they have good BJ's, and installing new Sportline bushings in the used LCA's.

Some new photos of the parts & current brakes have been uploaded to my website, and there is also a spreadsheet there with all the part numbers for the brake parts, LCA's, etc etc...

http://www.meimann.com/images/mercedes/W124_brakes/

Best regards,

omegabenz · #22 02-27-2004, 10:23 PM

On my brother's 87 300D, I put 500E ATE brakes on there, and I just bent the dust shield back to the ball joint. I think 3mm is enough from the disc to the dust shield.

On the car that I put the 500E brembos on, the dust sheilds were already modified for 560SL brakes, so infront of the ball joint it was cut. Forget about describing it, I will just take some pictures.

gsxr · #23 02-27-2004, 10:36 PM

Exactly - my stock brakes have about 3mm space on EACH side of the dust shield. The E420 rotors are 6mm deeper, taking away all that space. Basically even if I jammed the dust shield against the LCA, it would still possibly rub the rotor - just zero space available. If not there would be zero space on the back side and no more than 1mm to the rotor. Just too close, IMO. This is for the 294x25 E420 rotors. I don't know how the 300mm or 320mm front rotors would work. Note that all the 124's with 300/320 rotors use the 129 knuckle & hub.

BTW, my spreadsheet has been updated with corrected part numbers, current pricing, etc... make sure the copy you're using is dated Feb-24, 2004, or later.

omegabenz · #24 02-28-2004, 12:08 AM

I have an extra set of 500E rotors, and I have 600SL rotors at my house as well. I can give you all the measurements on the hat.

I think that E420 brakes have a weird hat vs a 500E. Also, a 190E LCA (Lower Control Arms) have smaller ball joints and the surrounding metal, maybe that is why ric didnt have any trouble.

Austin

gsxr · #25 02-28-2004, 12:11 PM

Austin,

That would be great, thanks! The measurement I need is the rear rotor friction surface to the back side of the hub flange. Basically, put the rotor face down, lay a straightedge across the back side, and measure down to the inner hub surface. I'll go measure mine too - I didn't write down the numbers, I just noted there was a 6.0-6.5mm difference between stock and E420.

About the 190E, I checked and I think the lower control arm is the same for the 190E "sportline" version (as my stock 300D LCA), but the standard 190E arm is a different number. Also the 190E uses a different knuckle and hub, which may move things out a few MM, and that's all it takes!

Chris Martens · #26 03-01-2004, 06:08 AM

Dave,

time for brake-upgrade again? Great!

Some remarks from my side: you confirmed my experiences that the 400E disks won't clear the standard LCA at the older W124. Here is my photo from 2001 showing that situation:

These are used (slightly rosted) but nearly new disks from a 300E-24 (M104 with CIS), the same as 400E, and a standard 300TE front axle.

The LCA for the 400E / 300E-24 etc. was also used in the R129 as well - so the welded ball joint should last better than the replaceable one.
I got the 400E-LCAs new for a fair price - not from the dealer! - so I took them.

Early 500E had the standard LCA with the fixed caliper brakes, but not the 400E ones. Must be the hub that is different but don't know for shure.

Still haven't finished my brake upgrade, me and the parts are waiting for spring!

best regards,
bis denn,
Christian

1989 300TE
1984 2.3-16

omegabenz · #27 03-02-2004, 10:25 PM

Mostly for dave, but others have a look.

600SL front rotors (used they start at 32mm I believe)
29.29 mm thick

42.88mm from back of flange to the inner braking surface sweep area

R129 front hub (right side)
71.88mm from where the brake disc sits to the upper caliper bolting flange, closest distance.

500E/500SL/320SL early model R129 front rotors (Brand new Zimmermann Cross drilled rotors, for sale might I add)

27.82mm thick

37.87mm flange to back sweep area of rotor.

Porsche 996 carerra 2002
27.36mm thick

61.41mm from pad contact area down to the mounting flange.

The rotor at the flange is 6mm thick, I didnt measure the other rotors, but I did the porsche ones for fun since I had my brake box out.

Do these help you?

gsxr · #28 03-03-2004, 12:06 AM

YES, thanks, that's a big help! From what you measured, it looks like the 300mm rotors (500E/500SL/320SL early model R129) will fit any W124, including my diesel. But the 320mm (600SL) front rotors will NOT fit without the late model lower control arm, assuming the 600SL calipers fit the 124 hub/knuckle properly. OR, the 600SL brakes work with the old LCA, and the R129 hub+knuckle (which is exactly what the 500E has). Basically the same deal as the E420 rotors. I need to measure the 124 hub to compare to the 129 numbers below. I'll add the data to my spreadsheet too.

For the record, I measured roughly 44mm from back of flange to the inner braking surface sweep area on the new E420 rotors, and 38mm from back of flange to the inner braking surface sweep area on the stock 284mm rotors. For the stock LCA & hub, the number needs to be about 40mm or less or the rotor won't clear the ball joint.

omegabenz · #29 03-03-2004, 12:18 AM

My friend put 1994 E420 brakes on his 1990 300D 3.5 Turbo, but he took the front brakes, and the hub that has the bearings, and then where the hub bolts onto, the spindle, which is pressed (attached) into the (I dont know).

The (I dont know) is bolted to the ball joint, the steering linkages, and the strut, and the two calipers bolts bolt to this piece.

What is the (I dont know) called?

I measured from the hub face where the rotor sits to the closest part where the caliper bolts to, on the measurements above.

Thanks,

gsxr · #30 03-03-2004, 12:31 AM

The hub is the round thingy that spins, with wheel bearings inside, that the rotor fits on to. The knuckle is the cast piece with the spindle sticking out of it. The ball joint fits into the bottom of the knuckle, and the strut bolts to the back of the knuckle. See image below.

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