Disc brake swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mike harris · 11-24-2017, 03:48 PM

I did a disc swap about 2 years ago but they've never really been that good. It was a master for 70 c10 disc swap, I have added a vacuum canister but it made no difference. The brakes work to an extent but I can't lock the car up. Booster is working fine but the pedal travels half way then it feels like it hits a wall and can't push pedal any further no matter how hard I try even with my size 17 boots on!!!. I disconnected the linkage to see how far the pedal should go before it stops and has loads of reserve travel left. Has anyone had a problem like this before? Or have any insight as to what might cause it? Wrong master? single booster not enough? Need a heavier boot? Thanks

**jocko** · 11-24-2017, 03:53 PM

Did the master cyl come with the Kit? i.e. is it a Disk/Drum mc? Is your truck a C10 or C20? Did the booster come with the kit? How are you certain the booster is good? (this sounds a bit like a booster to me, or at least part of it does). Pls describe your prop valve/distrib block - was that part of the kit also?
Brakes can be frustrating, eh? Isn't s UK size 17 equivalent to a US size 6? (

) You need Texas boots.

Mike harris · 11-24-2017, 04:04 PM

Haha I already converted the size for you guys

it's a c10, for some reason I bought the parts kinda separately but from the same seller as in I made my own kit, all parts (spindles, discs, calipers, master and prop valve) were listed for a c10 but I am kind of regretting not just buying a whole setup from summit designed as a kit. When I fire the motor the pedal drops about 1/2 inch and when I pull the vacuum pipe I can here it hiss so I figured that ment the booster was alright.

Mike harris · 11-24-2017, 04:06 PM

And yes it was all disc/drum equipment. At least the guy told me it was

**The Rocknrod** · 11-24-2017, 05:49 PM

I always make sure my master cylinder is made for the booster I purchase by checking the pushrod length between the booster and the M/C:
http://67-72chevytrucks.com/vboard/s...d.php?t=498293
http://67-72chevytrucks.com/vboard/s...d.php?t=686449
Then make sure my brake pedal ratio is correct:
http://67-72chevytrucks.com/vboard/s...d.php?t=686449

11-24-2017, 03:48 PM	#1
Mike harris Registered User Join Date: Mar 2016 Location: Bransgore. Dorset. United kingdom Posts: 61	Disc brake swap I did a disc swap about 2 years ago but they've never really been that good. It was a master for 70 c10 disc swap, I have added a vacuum canister but it made no difference. The brakes work to an extent but I can't lock the car up. Booster is working fine but the pedal travels half way then it feels like it hits a wall and can't push pedal any further no matter how hard I try even with my size 17 boots on!!!. I disconnected the linkage to see how far the pedal should go before it stops and has loads of reserve travel left. Has anyone had a problem like this before? Or have any insight as to what might cause it? Wrong master? single booster not enough? Need a heavier boot? Thanks

11-24-2017, 03:53 PM	#2
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,933	Re: Disc brake swap Did the master cyl come with the Kit? i.e. is it a Disk/Drum mc? Is your truck a C10 or C20? Did the booster come with the kit? How are you certain the booster is good? (this sounds a bit like a booster to me, or at least part of it does). Pls describe your prop valve/distrib block - was that part of the kit also? Brakes can be frustrating, eh? Isn't s UK size 17 equivalent to a US size 6? () You need Texas boots.

11-24-2017, 04:04 PM	#3
Mike harris Registered User Join Date: Mar 2016 Location: Bransgore. Dorset. United kingdom Posts: 61	Re: Disc brake swap Haha I already converted the size for you guys it's a c10, for some reason I bought the parts kinda separately but from the same seller as in I made my own kit, all parts (spindles, discs, calipers, master and prop valve) were listed for a c10 but I am kind of regretting not just buying a whole setup from summit designed as a kit. When I fire the motor the pedal drops about 1/2 inch and when I pull the vacuum pipe I can here it hiss so I figured that ment the booster was alright.

11-24-2017, 04:06 PM	#4
Mike harris Registered User Join Date: Mar 2016 Location: Bransgore. Dorset. United kingdom Posts: 61	Re: Disc brake swap And yes it was all disc/drum equipment. At least the guy told me it was

11-24-2017, 05:49 PM	#5
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: Disc brake swap I always make sure my master cylinder is made for the booster I purchase by checking the pushrod length between the booster and the M/C: http://67-72chevytrucks.com/vboard/s...d.php?t=498293 http://67-72chevytrucks.com/vboard/s...d.php?t=686449 Then make sure my brake pedal ratio is correct: http://67-72chevytrucks.com/vboard/s...d.php?t=686449 __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?



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