MASTER CYLINDER HELP.. smaller bore style..

[Xtremegmc80]

i converted my truck from drums to rear discs. got everything straightened out. now 1 thing left to do which mastercylinder should i get? i already bought a 74 corvette MC it fits, but the brake line doesnt fit. am i supposed to get the adaptor for them? thanks.. this truck is a 1980 gmc, d44 with 14ff.. hope u guys can help me out, cause someone on ck5 say it bolts right up. so i did. but are the brake line supposed to bolt up? or did i get the wrong mc? or was i supposed to get adaptor too?? thanks in advance.

 

[dremu]

If it were me, I'd try the stock MC first.

My K5 is running the stock master with discs on both ends, 10b/14FF, and I have no issues, no need for adjustable prop valve, etc.

-- A

 

[sta500666]

i converted my truck from drums to rear discs. got everything straightened out. now 1 thing left to do which mastercylinder should i get? i already bought a 74 corvette MC it fits, but the brake line doesnt fit. am i supposed to get the adaptor for them? thanks.. this truck is a 1980 gmc, d44 with 14ff.. hope u guys can help me out, cause someone on ck5 say it bolts right up. so i did. but are the brake line supposed to bolt up? or did i get the wrong mc? or was i supposed to get adaptor too?? thanks in advance.

Hey man, I literally just got done yesterday figuring my brakes out after 2 weeks of hell haha! Good news tho, I have the same things done to my truck like 14b rear disc conversion and d44 front. I did the swap this summer. I didnt know what to do as far as brakes I ended up using rediculusly larg calipers in the back which was part of the reason why it took so long to figure out how to get the system to work. But anyway the easiest fix is a new master cylinder. All I had to do to get my system to work was get a new master cylinder Part Number 101534 1977 K30 4x4 1 5/16” bore. I am still running the stock proportioning vavle and stock lines. It too about 45 minutes to completely bleed the brakes, but I had awesome stopping power now and I do have more pedal travle but my pedal doesnt hit the floor, and my brakes engauge before i have to push it down that far anyway.

So seriously all you need is that master cylinder, just make sure to bench bleed it!!

 

[dremu]

Hey man, I literally just got done yesterday figuring my brakes out after 2 weeks of hell haha! Good news tho, I have the same things done to my truck like 14b rear disc conversion and d44 front. I did the swap this summer. I didnt know what to do as far as brakes I ended up using rediculusly larg calipers in the back which was part of the reason why it took so long to figure out how to get the system to work. But anyway the easiest fix is a new master cylinder. All I had to do to get my system to work was get a new master cylinder Part Number 101534 1977 K30 4x4 1 5/16” bore. I am still running the stock proportioning vavle and stock lines. It too about 45 minutes to completely bleed the brakes, but I had awesome stopping power now and I do have more pedal travle but my pedal doesnt hit the floor, and my brakes engauge before i have to push it down that far anyway.

So seriously all you need is that master cylinder, just make sure to bench bleed it!!

Out of curiousity, what calipers did you use?

-- A

 

[sta500666]

Large 1979 Front 3/4-ton calipers with a 3 5/32'' piston... they are huge. I have 15 inch wheels also and I had to grind the calipers down haha. But like I said my braking power is awesome and I cant beilive I got it all to work with them that big, I thought I was ganna have to go get some eldorado calipers

 

[dremu]

Large 1979 Front 3/4-ton calipers with a 3 5/32'' piston... they are huge. I have 15 inch wheels also and I had to grind the calipers down haha. But like I said my braking power is awesome and I cant beilive I got it all to work with them that big, I thought I was ganna have to go get some eldorado calipers

As in for a D44 or 10b, Chevy 3/4?

-- A

 

[sta500666]

As in for a D44 or 10b, Chevy 3/4?

-- A

Yes, D44

 

[Xtremegmc80]

Hey man, I literally just got done yesterday figuring my brakes out after 2 weeks of hell haha! Good news tho, I have the same things done to my truck like 14b rear disc conversion and d44 front. I did the swap this summer. I didnt know what to do as far as brakes I ended up using rediculusly larg calipers in the back which was part of the reason why it took so long to figure out how to get the system to work. But anyway the easiest fix is a new master cylinder. All I had to do to get my system to work was get a new master cylinder Part Number 101534 1977 K30 4x4 1 5/16” bore. I am still running the stock proportioning vavle and stock lines. It too about 45 minutes to completely bleed the brakes, but I had awesome stopping power now and I do have more pedal travle but my pedal doesnt hit the floor, and my brakes engauge before i have to push it down that far anyway.

So seriously all you need is that master cylinder, just make sure to bench bleed it!!

alright.. i cant do anything til tuesday.. darn it! will return the vette MC and try the 77 K30 Mc.. thanks again!

 

[Xtremegmc80]

If it were me, I'd try the stock MC first.

My K5 is running the stock master with discs on both ends, 10b/14FF, and I have no issues, no need for adjustable prop valve, etc.

-- A

the stock Mc seems to be no good, its new not that new, but everytime i lock up the tires in the snow or even ice! when it was still on 1/2 tons.. the rear wont lock up. so im sure the mc is bad, will find out with the new mc.. thanks.

 

[Xtremegmc80]

forgot abt this thread. the 77 k 30 mc doesnt fit my booster, so i tried the 80 3/4 ton mc. now my truck has brake working, and pedal feels good. i still havent test driven her yet. still waitin on steering arm, will let u guys know! thanks.

 

[sta500666]

forgot abt this thread. the 77 k 30 mc doesnt fit my booster, so i tried the 80 3/4 ton mc. now my truck has brake working, and pedal feels good. i still havent test driven her yet. still waitin on steering arm, will let u guys know! thanks.

hmm... thats odd it didnt fit, but atleast it pointed you in the right direction!! I messed around for almost a month tryin to figure things out!

 

[Xtremegmc80]

hmm... thats odd it didnt fit, but atleast it pointed you in the right direction!! I messed around for almost a month tryin to figure things out!

yeah im hopin my mc will stop good or reasonable! i just have to wait til the arm arrives then take it for a test drive, if it fails, im gonna have to look into new booster from newer model, and get the newer disc'd brakes truck mc. so .. i hope i dont have to do all that. just gonna wait, im hopin to try it out this week

 

[sta500666]

hope it works out for ya!! My boster is stock on my 86, and the 1-ton MC fit perfectly.

 

[ShiftyK5]

Having brake issues myself and did a search and found this thread, so a 1 ton non hydroboost MC will fit on my 1/2 is what you guys are saying. no adapters or anything ?
and this will help my K5 stop much better ?
right now i'm not gettin hardly any fluid to my rear drums and my front discs barely stop the thing.

also could my power brake booster need replacing and how would i tell its bad other then it woould be a pita to push the pedal down ?