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jensht
Member
Date registered: Nov 2009
Location: Puchheim, Germany
Vehicle(s): 2001 Mercedes 290GDT
Posts: 29
| Stripped lower, front, brake caliper threads
Hi everyone, I took my W461 290GDT to the dealer for a technical inspection and emissions testing (German TÜV that's needed every two years) and the tester didn't appreciate my rear disks since they were right at the wear limit. Since it has been a while since the brakes had been done on the truck and I have noticed a degraded braking experience I decided to have the dealer replace both the front and rear rotors+pads. I got a call from the dealer that the lower brake caliper threads on both the left and right front got stripped while removing the bolts. They claim it probably is due to the age/mileage of the truck (16 years and 250,000km) and are not willing to cover the cost, or part of it. Now the big question, the dealer wants between EUR5000 - 7000 to replace both ends of the front axle since they would have to strip it all down to replace the carriers/hubs. They are not willing to rethread the hole or use a HeliCoil due to liability with the braking system. I spoke with one of the Mercedes mechanics on the side and he said if it was his car he would either try HeliCoil or finding an entire used front axle from another truck.
Wanting another opinion I took a photo and had another garage take a look. They won't do HeliCoil on brakes, but they think it should be fine to bore it out and rethread it. Does anyone have any experience if boring it out and rethreading it is a problem. It seems like the most painless and closest to original solution to me but I also don't want to have the caliper fall off when hitting the brakes.
Link to picture of what I mean: https://goo.gl/photos/fKbLYMQZwPSYiCLt9
It is the mounting hole to the left of the brake caliper
Edited by jensht 3/29/2017 1:20 PM
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bram_r
Expert
Date registered: Apr 2007
Location: the Netherlands
Vehicle(s): 1984 MB 280GE, 1982 MB 300GD, 1986 Subaru XT 4WD
Posts: 1659
| RE: Stripped lower, front, brake caliper threads
This has been done before by several people.
Some topic links:
http://pointedthree.com/disc/forums/showthread.php?tid=22307&posts=...
http://www.pointedthree.com/disc/forums/showthread.php?tid=16772&po...
Even did it myself:
http://www.pointedthree.com/disc/forums/showthread.php?tid=10748&po...
Made a fixture on drill column, to be 100 % in line with the bolt hole when drilling to helicoil size.
I'd say go ahead with the helicoil and save yourself some money.
gr. Bram |
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Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3186
| Re: Stripped lower, front, brake caliper threads
Time Serts are the way to go. Used them on the front calipers of my 463.
To me a more permanent solution than Helicoil.
Edited by Inkblotz 3/30/2017 7:21 AM
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D.vL
Member
Date registered: Sep 2007
Location: Belgium
Vehicle(s): W461 290 GD - LWB - 1997
Posts: 11
| Re: Stripped lower, front, brake caliper threads
Hi,
I have had the same problem with my 290GDT from 97 and 230.000km on the clock.
The problem I think is that the bolds have rust on the back and when you remove them you damage the inner thread.
I went for the Helicoil solution like Bram did.
The advantage with the helicoil is that you can use new original bolds. I did the repair 3 years back and last year I removed the calipers again to put a new hose and new grease in the ball joints. No problem at all with the helicoil
Good luck with your repair
Grts
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jensht
Member
Date registered: Nov 2009
Location: Puchheim, Germany
Vehicle(s): 2001 Mercedes 290GDT
Posts: 29
| RE: Stripped lower, front, brake caliper threads
Thanks for all the replies. Looks like HeliCoil and Timeserts aren't very popular for this application in Germany. I called 5 different independent shops and none will use them. What are the opinions on rethreading? |
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| RE: Stripped lower, front, brake caliper threads
jensht - 4/3/2017 1:30 PM
Thanks for all the replies. Looks like HeliCoil and Timeserts aren't very popular for this application in Germany. I called 5 different independent shops and none will use them. What are the opinions on rethreading?
Possibly because of TUV? |
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Inkblotz
Expert
Date registered: Apr 2006
Location: Georgia
Vehicle(s): 90 300GD "Thundering Turtle II", w/ 603A turbo
Posts: 3186
| RE: Stripped lower, front, brake caliper threads
jensht - 4/3/2017 1:30 PM
Thanks for all the replies. Looks like HeliCoil and Timeserts aren't very popular for this application in Germany. I called 5 different independent shops and none will use them. What are the opinions on rethreading?
If you rethread you will need to go with a larger bolt and drill a larger hole in the caliper ear. Unless you weld not shut and start fresh. |
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jensht
Member
Date registered: Nov 2009
Location: Puchheim, Germany
Vehicle(s): 2001 Mercedes 290GDT
Posts: 29
| Re: Stripped lower, front, brake caliper threads
So an update on this topic. I towed the truck to two different independent shops and both had a look and they can't do a HeliCoil and also say re-threading isn't an option. Neither stated that it against TÜV (German vehicle testing), but they say the application isn't suitable. Not having the tools, skill, or space I'll just have to accept that.
Since we'll be replacing the knuckles (A4603371306 and A4603371406), is there anything that would be worthwhile to replace while this is being done? |
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oskar
Elite Veteran
Date registered: Sep 2006
Location: Lyons, CO
Vehicle(s): 1981 280GE, 2002 G500, 280SE 4.5, Audi A4 1.8T
Posts: 708
| Re: Stripped lower, front, brake caliper threads
jensht - 4/25/2017 11:10 AM
So an update on this topic. I towed the truck to two different independent shops and both had a look and they can't do a HeliCoil and also say re-threading isn't an option. Neither stated that it against TÜV (German vehicle testing), but they say the application isn't suitable. Not having the tools, skill, or space I'll just have to accept that.
Since we'll be replacing the knuckles (A4603371306 and A4603371406), is there anything that would be worthwhile to replace while this is being done?
Einfach selber machen ... ( English: DIY )
Oskar |
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Aircruiser
Extreme Veteran
Date registered: Aug 2011
Location: Atlanta GA
Vehicle(s): 2000 G500, 1986 300GD, 2017 Porsche Cayenne Hybrid
Posts: 364
| Re: Stripped lower, front, brake caliper threads
I went a different route with my 460 Perrot two line calipers with some bleeder problems. I found some rebuildable calipers, split them, replaced seals and got rid of all of the messed up threads by mixing and matching caliper halves. I was lucky that the cylinder bores were good on the castings with good threads. It was an inexpensive and long term fix, finding the right used caliper and waiting for international shipping was the only pain.
Edit: My mistake, your problem threads are not on your calipers. Disregard.
Edited by Aircruiser 4/25/2017 6:25 PM
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