Elwood
3-7-77
- Location
- Long Beach, CA
I have the 5QM 615 126 B carrier.
7
How to retro-fit the 312mm front brakes to a Mk7 Golf
- Thread starter golfdave
- Start date
I have the 5QM 615 126 B carrier.
golfdave
Autocross Champion
- Location
- Scotland (U.K.)
- Car(s)
- Mk7 Golf GT Estate
That's the standard USA factory 288mm disc carrier...so you may have the 55mm pistons...so like "autovelocity"....
& NOT like me...as we get the 57mm piston 8V0 615 123 calliper for our 288mm discs..this caliper is that same piston size used on the 312mm GTI/GTD brakes....so a 288mm to 312mm disc swap only requires the carriers & discs...
Yours will require new callipers also to work 100%...
autovelocity
Passed Driver's Ed
- Location
- Canada
- Car(s)
- 18 R
Correct! just sucks I have to rebuy new pads, rotors and calipers.
Btw, I wonder how the existing master cylinder which was made for the 55mm calipers will work with the new 57mm calipers.
Cuzoe
Autocross Champion
- Location
- Los Angeles
I'm not retrofitting anything but I've been researching Master cylinders recently. I've got a set of Brembo 17z coming for my TDI and I'm concerned (to put it mildly, haha). But from what I can tell every mk7 has a 23.8mm master cylinder.
Both 7zap and parts.vw spec part numbers beginning 8V1 611 021. However, the R part number ends 021B while the TDI ends 021A. Research of both shows the same diameter. Could the stroke be different?
For what it's worth the GTI specs the 021B part and doesn't differentiate PP/non-PP. Makes sense that I haven't read any complaints about pedal feel when upgrading a non PP GTI to PP/R brakes.
The brake booster changed part numbers in December 2015, went from an ATE to a TRW part but did so for Golf/GTI/Rs.
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Both 7zap and parts.vw spec part numbers beginning 8V1 611 021. However, the R part number ends 021B while the TDI ends 021A. Research of both shows the same diameter. Could the stroke be different?
For what it's worth the GTI specs the 021B part and doesn't differentiate PP/non-PP. Makes sense that I haven't read any complaints about pedal feel when upgrading a non PP GTI to PP/R brakes.
The brake booster changed part numbers in December 2015, went from an ATE to a TRW part but did so for Golf/GTI/Rs.
Sent from my A0001 using Tapatalk
autovelocity
Passed Driver's Ed
- Location
- Canada
- Car(s)
- 18 R
I just looked at my master cylinder and it's a 5Q1 611 301C which surprisingly is used on a lot of GTI models.
https://parts.vw.com/p/Volkswagen_2...-RESERVOIR-Reservoir/64431410/5Q1611301C.html
This means the new 57mm calipers will be just fine with the existing master cylinder.
https://parts.vw.com/p/Volkswagen_2...-RESERVOIR-Reservoir/64431410/5Q1611301C.html
This means the new 57mm calipers will be just fine with the existing master cylinder.
Cuzoe
Autocross Champion
- Location
- Los Angeles
I believe you're looking at the master cylinder reservoir. The master cylinder itself sits underneath it.
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autovelocity
Passed Driver's Ed
- Location
- Canada
- Car(s)
- 18 R
Great! I thought the cylinder came with the reservoir thus using the same part #.
I'll look down there then.
Meh.. It's a 5Q1611021A which is also used on the AllTrack which also comes with the 312mm rotors stock..
No issues there then.
Last edited:
Cuzoe
Autocross Champion
- Location
- Los Angeles
Nice, I need to go see what part number is actually on my car. The parts breakdown on parts.vw says I could have the 8V1611021A or 5Q1611021A as fitted to your car (and the Alltrak). Your master cylinder is made by ATE, speced at 23.8mm (unsurpisingly). The part numbers I mentioned earlier are TRW units. Interestingly they have different part TRW part numbers.
8V1611021A - TRW No. PMK685 - 23.8mm
8V1611021B - TRW No. PML480 - 23.81mm
Can't say I'm concerned about a .01mm difference but I don't know if that's the only reason for the part number difference. The B seems to be specified for cars with 312/340mm brakes. Assuming we all have the same size master cylinder (as we appear to) I think I should be okay. To be sure my rough math shows the 17z kit will have a little more piston area than the Golf R brakes 3100ish sq mm versus 2800ish sq mm but with the same master cylinder.
I would like to drive an R to see how the brake pedal feels. Based on everything we have found here I have to think the pedal is softer than ours although the braking power is massively improved. My pedal is grabby to the point that I nearly put myself through the windshield the fist time I drive the MK7 after driving the MK4 or my wife's Corolla. This could give the illusion that the brakes are incredible, which I suppose is how the majority people want to feel about their brakes.
8V1611021A - TRW No. PMK685 - 23.8mm
8V1611021B - TRW No. PML480 - 23.81mm
Can't say I'm concerned about a .01mm difference but I don't know if that's the only reason for the part number difference. The B seems to be specified for cars with 312/340mm brakes. Assuming we all have the same size master cylinder (as we appear to) I think I should be okay. To be sure my rough math shows the 17z kit will have a little more piston area than the Golf R brakes 3100ish sq mm versus 2800ish sq mm but with the same master cylinder.
I would like to drive an R to see how the brake pedal feels. Based on everything we have found here I have to think the pedal is softer than ours although the braking power is massively improved. My pedal is grabby to the point that I nearly put myself through the windshield the fist time I drive the MK7 after driving the MK4 or my wife's Corolla. This could give the illusion that the brakes are incredible, which I suppose is how the majority people want to feel about their brakes.
autovelocity
Passed Driver's Ed
- Location
- Canada
- Car(s)
- 18 R
I got my parts ordered, however I ran across this site which is pretty good considering they tell you caliper piston diameter dimensions.
https://www.autodoc.co.uk/car-parts/oem/8v0615123
Oh and btw, the 8V0615123A caliper got replaced by 8V0615123D now.
https://www.autodoc.co.uk/car-parts/oem/8v0615123
Oh and btw, the 8V0615123A caliper got replaced by 8V0615123D now.
golfdave
Autocross Champion
- Location
- Scotland (U.K.)
- Car(s)
- Mk7 Golf GT Estate
its actually English UK site of a main German website..I got my brake discs & calliper brackets from this lot...
Cuzoe
Autocross Champion
- Location
- Los Angeles
Ever get a chance to look into those master cylinders?
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Sent from my A0001 using Tapatalk
autovelocity
Passed Driver's Ed
- Location
- Canada
- Car(s)
- 18 R
One thing I could not find out ahead of time is, if the brakeline from the existing 55mm caliper will properly mount on the new 57mm caliper.
More specifically the banjo bolt.
More specifically the banjo bolt.
golfdave
Autocross Champion
- Location
- Scotland (U.K.)
- Car(s)
- Mk7 Golf GT Estate
All the same, as the 55mm piston caliper uses the same casting as the 57mm piston caliper...
Also just double checked etka..there is a split around April 2015...ie before then is one part & after then is a different part...but all the same part (hose, banjo bolt) for all MK7 Golf front...inc "R"..
How can i tell if i have the 55mm piston or 57mm without removing anything from the car?
I have obdeleven handy.
golfdave
Autocross Champion
- Location
- Scotland (U.K.)
- Car(s)
- Mk7 Golf GT Estate
obd11 won't tell you...
it appears USA cars get 55mm pistons with 288mm discs.....Europe get 57mm pistons with 288mm discs...
only way 100% is to check you vin number agaist ETKA at the dealers parts dept & it will tell you which calipers are fitted...5QM is 55mm ---8V0 is 57mm
or remove the caliper & it should have 57 or 55 stamped into it on the back face near the piston...