The calipers I freshly installed on my 220D with new rotors and pads are not alighned perfectly. Both calipers drag the inside pad on the rotor, while keeping a slight space between the outside pad and rotor. Is it customary to place a thin piece of metal between the caliper and its mounting point to correct dragging issues like this? Where would I find a shim set? Or do I need to make them myself?

Any advice or feedback welcome.

Cassidy

Mabye I didnt explain myself thouroghly ... I think I need to insert a piece of metal between the caliper and its mount to change its position relative to the rotor. Does MB make shims for this? Is this SAFE?

Bumpity Bump

Never heard of doing anything like this, I'd recommend against doing it.
As long as the caliper casting isn't contacting the rotor, I don't see the sense in it (although I understand WHY you want to do it).
The pistons are what moves the pads in and out. Shimming will affect the position of the cast housing. You need to find out why the one side isn't contacting the rotor. The car wouldn't stop worth a crap with a situation like this. Is the car stopping OK or not? How hard is the one side dragging? Hard to turn the rotor by hand? Did you bleed the air out after replacing the calipers?
Do the new calipers appear to be the same as the old ones?

Gilly

PS 3 hours is a bit premature for a bumpety bump

Alignment shims are only used to get the pads and pistons perfectly perpendicular to the rotor.

If the pads are just at different distances from the rotor, they will both extend with no resistance to speak of until they contact the rotor equally. At that point, hydaulic pressure (provided by you foot on the pedal) will work equally on both sides.

Speaking of that, you DID pump the brakes back up after you put the pads in before you tried to drive if didn't you? Pedal will hit the floor repeatedly until you do!

If the pistons don't push the pads out to the rotor, something is definitely wrong.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Thanks for the advice, and sorry for the bump.

Anyhow, the calipers are fresh from a low mileage 1985 300D. They are NOT the same calipers as the 220D, but they bolt up fine with 300D rotors and pads. Everything is on the car right now except brake hoses.

I used a slight wedge to squeeze the caliper pistons open (with the bleeder valve open and hose plug off) and mounted them onto the disc and slid them into correct position. I would say there was 2/3 mm clearance between the open pads and rotor. I tightened down the two caliper bolts on each caliper and rechecked the clearances. Now, the inside pad on each caliper is squeezing the rotor. Both rotors are fairly hard to turn. The clearance didnt disappear, it just moved. Now, the outside pads have about 2/3 mm of travel before contacting the rotors, while the otherside is bound up on the rotor.

Using basic reasoning, I figured that I could simply place a 1/2mm thick piece of metal (cut and drilled for the caliper mounting bolt pattern) to relocate the caliper a wee bit to the inside of the vehicle. This would change the clearances on the caliper so that their was no pad contact on the rotor.

Do you see where I am going with this idea? Not sure if I made a mistake or if the 300D brake parts mount to a slightly different spindle/control arm assembly.

Cassidy

I wouldn't worry about it until the hoses are installed, the brake fluid is bled of air, and you drive it a few miles.

Gilly

I used a slight wedge to squeeze the caliper pistons open (with the bleeder valve open and hose plug off) and mounted them onto the disc and slid them into correct position. I would say there was 2/3 mm clearance between the open pads and rotor.

Cassidy

There are two types of disc pads for 123 series. 15mm wide on early models and 17mm wide on later (eg '85 300D), otherwise they are identical.

If you have 2 to 3mm clearance between pads and rotor with pistons fully back be sure you are using 17mm pads.

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Beagle