73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Garrcus on February 20, 2012, 12:28:22 pm
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Hey Guys,
85 Chevy K10/Manual
Quick question, I got a full service today and the tech checked the brake/clutch fluid levels. He pulled the rubber cup that sits directly under the clutch fluid reservoir cap. It was quite swollen which he said could be a sign that some other kind of fluid got in the system. Is this true? Or is it simply old?
Also where can I find a replacement rubber cup? I have searched online to no avail, I may not have the proper terminology when searching.
Any Help is greatly appreciated.
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It depends on what he means by "other kind of fluid", Yes there are certain fluids that can make the rubber seal/boot you are talking about to swell, but I don't know how they would get there.
More than likely your clutch cap rubber seal/boot is just bad. Try looking up clutch reservoir cap, then it might show a listing for just the rubber seal/boot portion.
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Here are some possibilities for the gasket:
http://www.autozone.com/autozone/parts/1985-Chevrolet-K10-1-2-ton-P-U-4WD/Master-Cylinder-Gasket/_/N-ijkpvZ8kngm (http://www.autozone.com/autozone/parts/1985-Chevrolet-K10-1-2-ton-P-U-4WD/Master-Cylinder-Gasket/_/N-ijkpvZ8kngm)
Are you the original owner? Is it possible someone added a little power steering fluid or some other type of oil to your master cylinder by accident, or cleaned the M/C cap/flushed the system with a petroleum based solvent? Rubber swells when exposed to petroleum solvents and oils. At the very least I would flush the system, replace the cap gasket, and inspect for fluid leaks at all the wheel cylinders and calipers.
Oh! And, welcome to the site!
Edit: Oops clutch slave cylinder not wheel cylinders.... Where was I? ::)
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Hey thanks for the input guys,
No I am not the original owner, have had the truck for about 7 months now and have replaced all sorts of stuff on it myself and basically learning as I go. My wife hates my new found hobby but I Love IT and wish I had taken an interest in mechanics earlier in life.
Anyway, the tech also mentioned that people will pour all sorts of different types of fluids into the wrong systems by simply not knowing what they are doing. However, I am wondering if this boot was even originally intended for this reservoir. Take a look at the pics (some with boot in reservoir as found and then also the boot removed) and let me know what you guys think. Overall the clutch is working great and have not had any problems thus far.
Also I ran by Autozone and picked up a Master Cylinder Gasket (also pictured) to see if my theory about this boot being some make shift stop gap by the previous owner was correct. However this new gasket also did not fit.
Do I need to start searching some junk yards?
Thanks again.
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Update:
I called the dealer and they said that GM has discontinued that seal. Called the local junk yards and they didn't have anything either. So went back to auto zone to try and see if I couldn't just replace the entire assembly with a newer set up to avoid not being able to find parts.
The guy who helped me knew exactly what I was talking about and pulled a clutch master cylinder from a 91 through 97 jeep cherokee, he took the cap off and tried it on my reservoir. Turns out that cap has the seal in the cap itself and is a perfect match. However they do not sell the cap by itself but only as part of the master cylinder which is $50. So I called Dodge and am having them order the part which is still $25. Seems a bit expensive for a such a simple part.
If anybody else has any other ideas let me know,
And thanks again for the feedback.
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I'm not totally sure what I'm looking at in the pics, but it looks like your reservoir just ran low and sucked it in (which of course would mean a leak). Are you losing fluid?
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im not sure if u need that gasket. i dont think that any of my trucks have ever had a gasket in clutch resivor :o.
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I agree with jaredts...it looks like you have a leak to address also.
That was a good deal finding another one for your reservoir. Mine is looking like a used condom too!
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im not sure if u need that gasket. i dont think that any of my trucks have ever had a gasket in clutch resivor :o.
It's a bladder like in the brake master cylinders. I believe they are there so you don't introduce air into hydraulic system.
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ok.. ill need to look at both my 87s next time im home and look again. hum..?
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Yes you need the rubber cap. Brake fluid is hygroscopic which means it absorbs moisture. The seal could have swollen due to water or contamination. I agree, flush and fill. Replace the cap or put a new reservoir if you can't find one.
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Yes you need the rubber cap. Brake fluid is hygroscopic which means it absorbs moisture. The seal could have swollen due to water or contamination. I agree, flush and fill. Replace the cap or put a new reservoir if you can't find one.
^This^ guy has all the answers.
Thanks again Vile for another detailed answer.
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Hey Thanks again guys for all of your feedback,
I don't think that I am leaking fluid but I know that the previous owner told me that he replaced the clutch within a few months before I bought it, perhaps he never filled the reservoir up properly but I will definitely flush and re-fill. I have never done that procedure before any tips?
Another question comes to mind, is that seal normally contained in the cap and through whatever went wrong sucked into that position. Or in other words is that the normal condition of the seal or was it vacuumed into that condition because of dead space, leak or other situation. Are your seals more in line with my last pic that I posted of the seal that fits later models or the cup like shape of mine.
Thanks again.
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If I remember right it is a cup like kind of the size of a K-cup from a Kerig, the ridge at the top is the gasket. It is about 1.25" or so deep and if you overfill it makes a mess. My hose going to the clutch master is cracked real bad. It would be nice to know if anyone knows of replacement parts for all the hydraulic parts
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It is cup shaped. If you can get it to lay flat and it stays that way and your clutch works as it should, I would leave it.
Zeig just get a pice of hose that is the same size from your local parts store.
as far as the line; A brake line can be used in between the clutch and slave cylinder.
There is no reason to touch any of the hydraulic clutch linkage to replace a clutch, except maye to move the slave cylinder out of the way.
Both the clutch and slave cylinders are available in your local parts stores.
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Alright so after doing a bunch more research online I found a couple more forums discussing this, it turns out that what the GM parts guy told me is correct. They do not make the cup diaphragm any longer and you cannot even buy one in a master cylinder kit or any other clutch kits sold. So if you have one treat it with care.
The jeep cherokee replacement cap with the seal integrated into the cap itself is my next option but I am worried that since there will only be a seal at the rim and nothing protruding down into the reservoir that it will not operate properly. Correct me if I am wrong but the point of that cup seal is to eliminate the possibility of air and moisture getting into the system by taking up that space and also acting as a fill line as to not overfill the reservoir. So should I just use the seal-in-cap replacement and fill it all the way up to eliminate the empty space or judge the fill line as to where the bottom of the cup seal would have been and leave the rest of the space empty? I really don't know if that will cause any problems or not?
Thanks again guys.
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Not to sound to simple here but why don't you just try it?
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Yeah, that is my next option, just looking to get as much info as possible before trying this. Money is tight and I just want to try and avoid having to replace other parts through my ignorance in the area. I'll let you guys know how it works out,
Thanks again for all the help.
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Resolution:
Alright so I went ahead and ordered the 91-97 Jeep Cherokee cap replacement. The cap is actually the exact same cap and comes with a new diaphragm somewhat similar to the old one which is awesome... problem solved. Working condition--so far so good.
Thanks again to all of your feedback guys.
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Great news, please post the part # please. Thanks and glad you found a solution.
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Part number would be nice. Someday someone is going to have the same problem and see this post and be glad you figured this out for them. This site has helped me with little odds and ends so many times its not funny. Thanks again Chris for hosting such a helpful site.
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91-97 Jeep Cherokee clutch reservoir cap and diaphragm replacement part #4741671. ($25.00 through dealership)
Fit my 85 Chevy K10 perfectly.
And yes this site rocks!!!!!
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Thanks for the part #!!!