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Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 5:26 pm
by Daewoo
AlanMcR wrote:Never seen this "spacer". Not sure what was referenced. In any case it is clear from the picture that the the pistons are pushed way out trying to reach the unvented disk. This is a vented disk caliper. You are very this did not result in a catastrophic brake failure.


Are you saying wrong parts were put into brake component assembly? If so this is just so damn scary to say the least

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 5:58 pm
by Court
It is all very curious since I did ask Guido to quote parts for me which he kindly did. Freight is the killer of any importing at least for brakes parts. So I did not buy from him but he did accompany the quote with exploded parts diagram and the relevant front brake diagram shows a solid not vented rotor!!!

So.... what now? Still have not removed the calipers so have at least a day to sort this out. I now recall being asked by MB Vancouver if existing rotors were vented or not since apparently they had a possibility to supply vented or not. Ok so how do I resolve this definitively I ask myself.

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 9:10 pm
by DesertStar
Court wrote:

Ok so how do I resolve this definitively I ask myself.


Like I said earlier, identify which axle you have. VIN datacard will show as well as the tag on the axle itself...right side facing front.

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 9:20 pm
by AlanMcR
Court, you need to take the parts diagrams with a grain of salt. The parts picture that pulls up for me also shows a solid disk. The actual part is vented. What part number did Guido quote you?

Anyway. I measured the opening of my calipers, though somewhat crudely, since I was too lazy to take the wheel off. The mouth is about 75mm, maybe a little less.

You mentioned that you had to push the pistons way back. The outside pistons aren't way back, rather they are near their extension limit as shown in the picture. While we are looking at the picture, that bolt in the center has no business being there. There is a specialized spring pin that crosses the chasm and holds the flat spring (not seen in the picture) in place.

Before you do push the pistons all the way back in, check the fluid reservoir to be sure it doesn't overflow.

file.jpg

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 9:32 pm
by Court
Hi Alan,

That bolt holds the brake wear sensors. See photo with sensor and retaining clip with pin. The wear sensors are longer than what is used now. The bolt goes through brass hole on the sensor assembly.


C3B0A3E4-65CE-405F-910B-BC5F2D4E7164.jpeg

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 10:02 pm
by AlanMcR
Ah, the angle fooled me. Measure the caliper opening.

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 10:05 pm
by Mercano
That looks correct to me, photos can be deceiving though. The pad retaining clip is also correct for non vented discs, assuming it fit correctly.
Here’s a picture of a wide caliper.

Re: Disc brake caliper bolts extremely tight!!!

Posted: Mon May 20, 2019 10:27 pm
by offroad-world
normally 300GDT have vented rotors , so they have wider ( different ) calipers . Courts VIN number shows non vented calipers even as the G has brake rotors in the back ( different rear axle than drum axle ) .

maybe as japan cars cannot drive that fast they mounted non vented rotors on new cars , MB did such things . to swap out these parts to vented rotors i would do later when i get the calipers cheap out of a G500 non amg for example . i would bring the G on the street at first .

mfg. guido .

Re: Disc brake caliper bolts extremely tight!!!

Posted: Tue May 21, 2019 9:10 am
by Court
Thanks everyone. Here is a photo of distance between calipers which I get to be 65mm.

05B56911-9C39-4609-A8F2-7A4702D33C73.jpeg


If all is correct for solid rotors then I will proceed. I expect vented rotors are better but I am not about to go finding wider calipers. I think to keep this original as possible is desirable.

Now to get that dam bolt off. Going in search of a high quality 19 mm 6 point box end and a flare wrench to fit the hydraulic fitting.

Re: Disc brake caliper bolts extremely tight!!!

Posted: Tue May 21, 2019 9:26 am
by vadimivanovich
Only buy a quality flare wrench. It helps to heat the fitting with a propane torch and also spray some penetrating oil. Crack it loose and work it back & forth to free up the threads.