Been under my '82 K2500 for three days now,replacing rotted brake lines..oh the joy..
...my LEAST favorite job on any vehicle,or at least in the top 3..
I had a rebuilt master cylinder off my '77 K2500 and my '82 needed one,its master cylinder leaked out of the rear since the day I got it 6 years ago,so the rear brake chamber in it would lose its fliud and most likely didn't pump any fluid to the rear wheel cylinders (which were leaky anyway,so that was actually good!)..I replaced the rear wheel cylinders yesterday,and when I put the master cylinder on,I had some "problems"..
The master cyl. I'm using was on a vaccuum booster from a typical gas engined truck,but my '82 is a diesel,has hydroboost brakes..the master cylinders look identical where they bolt up and the push rod depth appears to be the same,the only difference I saw was the one from the truck with vacuum brakes had a rubber seal/o-ring on it,that didn't seem to affect it any,it bolted right up and seemed to have the same free play as the old one did at the pedal...the old master cyl. was a rectangular one with a square cover,had two chambers,one up front was much larger than the rearmost one,and it had one "bail" to hold on the cover..the one I'm putting on has an oval cover,and two chambers both the same size..
When Iwent to put the two brake lines on,the fittings were not the correct size--being a former parts counterman,I know many times you needed adapters to get them to fit..(in fact the master cyl HAD two in it,but they were not the correct size)..but I found if I swapped the brake lines around so that the one that used to be up front was now in the rear and vice versa,they screwed right in perfectly...
I'm wondering if this is going to screw everything up..I know drum brake master cylinders usually have a check valve on the drum portion of it...now I'm wondering if that will make the calipers drag ,if I in fact now have the line for the front brakes hooked to the port in the master that normally was used for the rear brakes..
I suppose I could go hunt down some adapters so the lines will go in the ports the same way as they did on the old master cyl,but those will cost half as much as another rebuilt master cyl. will..since the one I'm trying to use *might" have had some issues from sitting in my shed for 4 years I'm kind of reluctant to waste time and money looking for adapters...(money I dont have,or I'd just go get a rebuilt master cyl just like the old one!)...
By the way,I had to use one of those adapters off the master cyl, on the proportioning valve,GM decided to put a "mongrel" 9/16x18 thread on the 1/4"brake line going to the rear brakes,instead of the "right" fitting size that comes on the new lines..(basterds!)..the front passenger side brake line also has a much larger thread fitting at that valve,and a real tight 90 degree bend in it too!--no room to put an adapter in it,it'll hit the vrossmember--and since I had doubts about getting the old fitting off and salvaging it,I said screw replacing that line!--it looks pretty solid despite being original,I hope it dont pop on me this winter...that line and the two coming from the master cyl will be the last 3 originals on the truck--ALL the rubber hoses should be ditched too,the steel on the front ones are all barnacles,and the rear one has cracks and is original-but I dont have 65 bucks more for three new hoses
right now--I'll have to keep my eyes open at the junkyard for some that might have been replaced recently..
Anyone have any experiences with swapping the lines around at the master cylinder??..I'll probably have all the brake lines hooked up later today and am going to see if I can bleed the brakes alone sucessfully..cant use my home brewed vaccuum bleeder with a diesel,no vacuum!..Doah:..
...my LEAST favorite job on any vehicle,or at least in the top 3..I had a rebuilt master cylinder off my '77 K2500 and my '82 needed one,its master cylinder leaked out of the rear since the day I got it 6 years ago,so the rear brake chamber in it would lose its fliud and most likely didn't pump any fluid to the rear wheel cylinders (which were leaky anyway,so that was actually good!)..I replaced the rear wheel cylinders yesterday,and when I put the master cylinder on,I had some "problems"..
The master cyl. I'm using was on a vaccuum booster from a typical gas engined truck,but my '82 is a diesel,has hydroboost brakes..the master cylinders look identical where they bolt up and the push rod depth appears to be the same,the only difference I saw was the one from the truck with vacuum brakes had a rubber seal/o-ring on it,that didn't seem to affect it any,it bolted right up and seemed to have the same free play as the old one did at the pedal...the old master cyl. was a rectangular one with a square cover,had two chambers,one up front was much larger than the rearmost one,and it had one "bail" to hold on the cover..the one I'm putting on has an oval cover,and two chambers both the same size..
When Iwent to put the two brake lines on,the fittings were not the correct size--being a former parts counterman,I know many times you needed adapters to get them to fit..(in fact the master cyl HAD two in it,but they were not the correct size)..but I found if I swapped the brake lines around so that the one that used to be up front was now in the rear and vice versa,they screwed right in perfectly...
I'm wondering if this is going to screw everything up..I know drum brake master cylinders usually have a check valve on the drum portion of it...now I'm wondering if that will make the calipers drag ,if I in fact now have the line for the front brakes hooked to the port in the master that normally was used for the rear brakes..
I suppose I could go hunt down some adapters so the lines will go in the ports the same way as they did on the old master cyl,but those will cost half as much as another rebuilt master cyl. will..since the one I'm trying to use *might" have had some issues from sitting in my shed for 4 years I'm kind of reluctant to waste time and money looking for adapters...(money I dont have,or I'd just go get a rebuilt master cyl just like the old one!)...
By the way,I had to use one of those adapters off the master cyl, on the proportioning valve,GM decided to put a "mongrel" 9/16x18 thread on the 1/4"brake line going to the rear brakes,instead of the "right" fitting size that comes on the new lines..(basterds!)..the front passenger side brake line also has a much larger thread fitting at that valve,and a real tight 90 degree bend in it too!--no room to put an adapter in it,it'll hit the vrossmember--and since I had doubts about getting the old fitting off and salvaging it,I said screw replacing that line!--it looks pretty solid despite being original,I hope it dont pop on me this winter...that line and the two coming from the master cyl will be the last 3 originals on the truck--ALL the rubber hoses should be ditched too,the steel on the front ones are all barnacles,and the rear one has cracks and is original-but I dont have 65 bucks more for three new hoses
right now--I'll have to keep my eyes open at the junkyard for some that might have been replaced recently..
Anyone have any experiences with swapping the lines around at the master cylinder??..I'll probably have all the brake lines hooked up later today and am going to see if I can bleed the brakes alone sucessfully..cant use my home brewed vaccuum bleeder with a diesel,no vacuum!..Doah:..
