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Disc brake caliper bolts extremely tight!!!

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Court
Posts: 582

Re: Disc brake caliper bolts extremely tight!!!

Post#131 » Wed May 22, 2019 8:19 am

Hi Mercano,

That information re bolts is exactly what I have and explains everything I have experienced. It is interesting to contemplate the engineering reasoning behind the design of this. On pondering this I think renewing the bottom bolts is probably a good idea while the top bolt less so. Although the cost is minimally different.

I have learned quite a bit during this exercise. Likely never to be used again!! As someone’s tag line here says. Experience is what you have after you needed it. This is exactly my situation.

Court
Posts: 582

Re: Disc brake caliper bolts extremely tight!!!

Post#132 » Thu May 23, 2019 3:12 pm

Those individual M19 bolts are $19 each!!! for the lower ones and $10 CDN for the upper ones.

Does anyone have the torque values for those? Not sure if I will replace them or not yet.

Thanks. Soon this thread will be done I hope.

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cal_w460
Posts: 1982

Re: Disc brake caliper bolts extremely tight!!!

Post#133 » Sat May 25, 2019 11:42 pm

Normally special 12.9 hardened bolts are pretty expensive, especially when buying one or two only. Even if not MB.

If you have the part number there will be cheaper sources. But shipping / customs / tax will add up aswell.
w460.333 1982 Colorado Beige 300 GD OM617.931

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cal_w460
Posts: 1982

Re: Disc brake caliper bolts extremely tight!!!

Post#134 » Sun May 26, 2019 3:32 am

Does your caliper bolts look like this?

IMG_2266.JPG
w460.333 1982 Colorado Beige 300 GD OM617.931

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inkblotz
Posts: 5078

Re: Disc brake caliper bolts extremely tight!!!

Post#135 » Sun May 26, 2019 3:39 am

RE the caliper spacer.
The 460 and early model 463s with non vented discs can be converted to vented discs with modifications to the calipers using the afor mentioned spacer and 4 tiny O rings. I did this rebuild on my 463 which now has vented discs. I had a local machinist draft some technical drawings to recreate this spacer.

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cal_w460
Posts: 1982

Re: Disc brake caliper bolts extremely tight!!!

Post#136 » Sun May 26, 2019 3:45 am

The OEM front brake caliper bolts that I posted a picture of have these part numbers:

1 pcs A4604210271 (black bolt) 9.20 EUR
1 pcs A4609900101 (grey bolt) 6.00 EUR

Incl. VAT.
w460.333 1982 Colorado Beige 300 GD OM617.931

Court
Posts: 582

Re: Disc brake caliper bolts extremely tight!!!

Post#137 » Sun May 26, 2019 7:45 am

Yes those look about right. I have ordered. Also I note it is recommended to run a tap down the lower hole to dress up the threads. I guess to clean out the old locktite.

Court
Posts: 582

Re: Disc brake caliper bolts extremely tight!!!

Post#138 » Wed May 29, 2019 3:57 pm

Finally got my bolts and started to do Rhs caliper.

Thinking it would be a piece of cake I decided to undo the hydraulic line at the yellow arrow location on the photo ( behind the plate holding the transition from flex to hard lines. Using my flare wrench as suggested by Mercano it was no problem but the hard line extends quite a distance it seems “inside” past the plate so no wiggle room to move it back without removing the two mounting bolts it seemed. Anyway going to need an extra set of hands “just in case” then can hold the calipers when bolts out and sort of rotate push back hard line to clear the opening.

Or do people release it at the caliper? or both? Removing the hard line completely in advance?

I think these two hard lines would benefit from being flexible or does that cause too much repeated flexing upon brake application?

B25C3A56-30C8-4186-91AE-05F8913343D0.jpeg


A5B0B28F-09FF-43C2-BDDB-28DD6EC79431.jpeg


Also one more question. In the photo of the brake fluid reservoir just in from you can see a place to open a blind nut cap. What is this for? Is it a different way to bleed the system?

Thanks in advance.

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inkblotz
Posts: 5078

Re: Disc brake caliper bolts extremely tight!!!

Post#139 » Wed May 29, 2019 4:43 pm

I usually grab a bungee, piece of rope or coat hanger hang the caliper from the spring rather than letting it drop and I can work from there

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DesertStar
Posts: 1373

Re: Disc brake caliper bolts extremely tight!!!

Post#140 » Wed May 29, 2019 4:57 pm

Isn't there a clip, that holds flex line to bracket, at where the hard line connects to flex line fitting (at yellow arrow) ? Removal should allow wiggle room or less tension to remove connection at caliper. I am pretty sure that's what I did.

Edit: I am under the impression you are removing caliper, if not than Inkblotz method above.
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