Brake Master Cylinder and Brake Booster Help!!!!

[rsl0311usmc]

Hi everyone I got a bad leak with the above parts especially the Brake Booster it's literally dripping. Now I want to make sure I am getting the right parts. The brake booster looks identical and they only list one on Oriellys. But the master cylinder has me thrown off. The brake code is both JB8 but there are two with different casting stamped codes 1925 and 1605. Which one is the correct one??? I will put the links below to both master cylinders and the brake booster I am purchasing. Any help would be really appreciated. Thanks everyone

https://www.oreillyauto.com/detail/c/select/brakes/brake-hydraulics/brake-master-cylinder/3bff094046ed/brakebest-select-brake-master-cylinder-new/ohh0/nmc11309/v/a/3454/automotive-truck-1984-chevrolet-k30-pickup-4wd?q=brake+master+cylinder&pos=0

https://www.oreillyauto.com/detail/c/select/brakes/brake-hydraulics/brake-master-cylinder/3bff094046ed/brakebest-select-brake-master-cylinder-new/ohh0/nmc11364/v/a/3454/automotive-truck-1984-chevrolet-k30-pickup-4wd?q=brake+master+cylinder&pos=1

https://www.oreillyauto.com/detail/c/brakebest-brakes/brakes/brake-hydraulics/power-brake-booster/69bab478e25a/brakebest-power-brake-booster-remanufactured/obh3/527307/v/a/3454/automotive-truck-1984-chevrolet-k30-pickup-4wd?q=power+brake+booster&pos=0

 

[WWRD99]

Hi everyone I got a bad leak with the above parts especially the Brake Booster it's literally dripping. Now I want to make sure I am getting the right parts. The brake booster looks identical and they only list one on Oriellys. But the master cylinder has me thrown off. The brake code is both JB8 but there are two with different casting stamped codes 1925 and 1605. Which one is the correct one??? I will put the links below to both master cylinders and the brake booster I am purchasing. Any help would be really appreciated. Thanks everyone

https://www.oreillyauto.com/detail/c/select/brakes/brake-hydraulics/brake-master-cylinder/3bff094046ed/brakebest-select-brake-master-cylinder-new/ohh0/nmc11309/v/a/3454/automotive-truck-1984-chevrolet-k30-pickup-4wd?q=brake+master+cylinder&pos=0

https://www.oreillyauto.com/detail/c/select/brakes/brake-hydraulics/brake-master-cylinder/3bff094046ed/brakebest-select-brake-master-cylinder-new/ohh0/nmc11364/v/a/3454/automotive-truck-1984-chevrolet-k30-pickup-4wd?q=brake+master+cylinder&pos=1

https://www.oreillyauto.com/detail/c/brakebest-brakes/brakes/brake-hydraulics/power-brake-booster/69bab478e25a/brakebest-power-brake-booster-remanufactured/obh3/527307/v/a/3454/automotive-truck-1984-chevrolet-k30-pickup-4wd?q=power+brake+booster&pos=0

Ok start with what is it, pics of the leaking area helps a ton as well. Hoses at the hydraboost can leak too.

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[rsl0311usmc]

Ok start with what is it, pics of the leaking area helps a ton as well. Hoses at the hydraboost can leak too.

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I am currently not near the truck to take photos but it's definitely leaking especially under pressure and not from the hoses. It's on the bottom of the hydraboost. I dried it off drove it and watched it drip especially after hitting the brakes. The truck sat for like 8 years so I am sure the rubber seals are gone. I definitely need to get parts ordered because I can't drive it. Do you have any idea what the codes are and if those parts are correct mainly the master cylinder?

 

[WWRD99]

Is it a blazer a truck?

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[rsl0311usmc]

Is it a blazer a truck?

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No it's the m1008 truck version. It's leaking were the hydroboost bolts together but on the bottom btw. It's literally dripping down on to the leaf spring and ground. The thing has to be shot. I want to obviously replace the hydroboost and the master cylinder while I am at it. Those two master cylinders I can't tell the difference other than the codes unless I am missing something?? I appreciate your help.

 

[rsl0311usmc]

This is were it's leaking on the bottom of the hydroboost

 

[WWRD99]

The booster is just a gasket. Pretty easy to change. Tons of kits out there. The master fits the 1 ton I think. I don't have that store around me so not sure exactly what it is.

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[rsl0311usmc]

The booster is just a gasket. Pretty easy to change. Tons of kits out there. The master fits the 1 ton I think. I don't have that store around me so not sure exactly what it is.

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Really that's all it is a gasket? But were can you get one nowadays? What's the 1925 casting stamp?

 

[cucvrus]

Get the rebuilt booster and master cylinder. That is the quick fix and the easiest. Save the old one till you have the rebuilt one installed, there may be a rod or other part you need. Last one I had apart 20 years ago was corroded and leak again a short time after putting the seals in it. If you were closer, I would give you a used one. I have parts I use for cores when I buy replacement parts. Good Luck. 15mm deep swivel socket and a long extension is about all the specialty tools you will need. Line wrenches of course.

 

[WWRD99]

Really that's all it is a gasket? But were can you get one nowadays? What's the 1925 casting stamp?

I've got about 75 kits on hand right now for those. It's the double o gasket that is the one that goes where you pointed to. There's a few videos out there plus it makes it nice to have the booster nut socket too. Nothing magical about it. Brake master I don't have kits for but they're easier than the booster. Probably a 20 kit for those.

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[rsl0311usmc]

Get the rebuilt booster and master cylinder. That is the quick fix and the easiest. Save the old one till you have the rebuilt one installed, there may be a rod or other part you need. Last one I had apart 20 years ago was corroded and leak again a short time after putting the seals in it. If you were closer, I would give you a used one. I have parts I use for cores when I buy replacement parts. Good Luck. 15mm deep swivel socket and a long extension is about all the specialty tools you will need. Line wrenches of course.

OK I purchased both on Oriellys. I hope I got the correct master cylinder as there are two listed. I went with the 1925. I was thinking the same thing as to holding onto the old one. The new one I purchased I think has a lifetime warranty at least. I saw the thing was also wet were the rod is by the brake pedal which I forgot to add. Now another thing. I have added a little power steering fluid to this truck when I got it and I am pretty sure now by the looks of the red color it had the oem atf in it. When I do this project should I flush it and add atf or power steering fluid? Also is a flush sufficient enough as sucking it out of the resivor?

 

[rsl0311usmc]

I've got about 75 kits on hand right now for those. It's the double o gasket that is the one that goes where you pointed to. There's a few videos out there plus it makes it nice to have the booster nut socket too. Nothing magical about it. Brake master I don't have kits for but they're easier than the booster. Probably a 20 kit for those.

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I am definitely going to have to take you up on that kit. I have learned already with this truck to not throw away anything like I did with the oem starter

 

[rsl0311usmc]

What's everyone's opinion on atf or power steering fluid in the power steering resivor? I think I may have mixed the two accidentally and I may suck all of it out and just fill it with either one. The reason I ask is I believe it works with the hydroboost I am putting on.

 

[cucvrus]

I use Power Steering fluid. Only because that is what GM had in them from the factory. I still use power steering fluid in power steering and ATF in Automatic transmissions. I have a Kubota and use Kubota UTD hydraulic oil in the tractor hydraulic system. Some guys just use AW32 hydraulic oil. My choice. It only cost a few dollars more to do the job right. Do as you wish. Have a Great Day.

 

[WWRD99]

What's everyone's opinion on atf or power steering fluid in the power steering resivor? I think I may have mixed the two accidentally and I may suck all of it out and just fill it with either one. The reason I ask is I believe it works with the hydroboost I am putting on.

If you have dexron 3 in it that'll clean it out some. Could flush it a few times with more then work over into the clear power steering fluid. Only time you'd know if you're in a cold climate the steering for the first 20 seconds is a little tight since it's thicker. Tm calls for dexron 3 for top off but factory is power steering fluid. They did that because it's one common fluid under the hood. POI...look for dexron 3 not the newer stuff that's expensive. I find it at tractor supply where I'm at.

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[rsl0311usmc]

If you have dexron 3 in it that'll clean it out some. Could flush it a few times with more then work over into the clear power steering fluid. Only time you'd know if you're in a cold climate the steering for the first 20 seconds is a little tight since it's thicker. Tm calls for dexron 3 for top off but factory is power steering fluid. They did that because it's one common fluid under the hood. POI...look for dexron 3 not the newer stuff that's expensive. I find it at tractor supply where I'm at.

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OK I appreciate all the help. I almost finished everything up today and it wasn't to bad. The hydroboost is definitely beat up and there was nasty rust crud were the master cylinder goes into the hydroboost. I have to get a new power steering hose, the one from the hydroboost to pump because the fitting going into the hydroboost cross threaded on me. But other than that everything is together and I stuck with dot 5 also. My power steering pump has always had a small leak also. So I am wondering if you or anyone has tried lucas power steering stop leak for the fluid instead of the dextron? It says it's guaranteed to stop leaks.

 

[WWRD99]

OK I appreciate all the help. I almost finished everything up today and it wasn't to bad. The hydroboost is definitely beat up and there was nasty rust crud were the master cylinder goes into the hydroboost. I have to get a new power steering hose, the one from the hydroboost to pump because the fitting going into the hydroboost cross threaded on me. But other than that everything is together and I stuck with dot 5 also. My power steering pump has always had a small leak also. So I am wondering if you or anyone has tried lucas power steering stop leak for the fluid instead of the dextron? It says it's guaranteed to stop leaks.
View attachment 914165

I haven't put much stock in those stop leak things, they will swell up the front seal a little bit if it's leaking a little. On a hose it's a no go. I usually just get a reman pump and pop it in the case. As far as the line if the rest is ok just get another end and double flare the line. I'd watch that fluid good. Just in case someone used dot 3 in it. I'd flush out the entire system with the dot 5...find a sticker online that says dot 5 only on it and put it on the master cover. Could save you a serious pita problem.

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[87cr250r]

Anything that causes a seal to swell is damaging it.

Your local auto parts store has seal kits for GM power steering pumps. It costs all of $10 to rebuild one.

Sometimes they leak when the reservoir gets bent trying to tension a belt. In this case a kit won't do you so well.

 

[cucvrus]

Same deal. Just get a remanufactured power steering pump for a diesel. It has 3 line one output and 2 returns. No worries and warranted for life.

 

[rsl0311usmc]

Anything that causes a seal to swell is damaging it.

Your local auto parts store has seal kits for GM power steering pumps. It costs all of $10 to rebuild one.

Sometimes they leak when the reservoir gets bent trying to tension a belt. In this case a lot won't do you so well.

Yeah what you are saying is kinda what I was thinking with that. I really don't like band aid fixes. The pump is definitely bent in areas from tightening the belt and all. I heard that lucas stuff is super thick anyways.