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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1980 gold on June 29, 2011, 12:27:29 am

Title: 87 hydraulic clutch
Post by: 1980 gold on June 29, 2011, 12:27:29 am
my  friend drove my 87 4x4 swb today and said my clutch is harder (pedal feel) than his 70 c10 with a mechanical clutch. he couldn't believe it was hydraulic. i did notice it was hard but i figured its not a car so.. is there anything i could check or fix this?
Title: Re: 87 hydraulic clutch
Post by: 1980c10 on June 29, 2011, 10:24:43 pm
I have converted two clutches to hydraulic set ups from mechanical and both pushed a little harder(but I also replaced both clutches at the same time). It may also be that his clutch is a little more worn than yours. If the amount of pressure seems reasonable then it is probably fine.
Title: Re: 87 hydraulic clutch
Post by: snibook7537 on June 30, 2011, 03:11:13 am
I dunno if it helps because my clutch is a really heavy duty one but the pedal in my 87 V3500 is a LOT heavier than in my 76 c-10 with a 454 clutch and pressure plate.  So not sure if it's really the same but the hydro clutch is a lot heavier.  Also I would any day take a mechanical linkage clutch over a hydro one, feel is nicer and no bleeding in my opinion adjusting it is way worth the feel.
 
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on June 30, 2011, 12:29:20 pm
i guess when you think of hydraulic it kinda sounds like it should be an easier pedal but your 87 is a hydraulic clutch and you say the pedal feels harder than your c10 mechanical?
Title: Re: 87 hydraulic clutch
Post by: zieg85 on June 30, 2011, 12:49:32 pm
Because of the way the clutch linkage is on the 73 and newer it is harder than the previous years for some reason.  I had a 69 and 72 both of which was easier than my 85 hydraulic set up.  My 86 hydraulic set up is as easy as a foreign car which leads me to believe the key is the pressure plate.  I know my 85 has had one clutch put in it by my uncle who went heavy duty all the way because he hauled a old heavy 35ft fifth wheel.  My 86 more than likely is original with only 70K original on it. 
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on June 30, 2011, 01:20:33 pm
that sounds good, would you reccomend a clutch? i read online the centerforce dual friction is a good one for an easier pedal but i'm not sure
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 03, 2011, 04:29:43 pm
i was also reading about hydraulic throw out bearings and the idea that the slave cylinder is partially seized. gotta look into all of it  i guess i just don't want to change parts just to change parts rather get a good opinion from more knowledgeable people than myself
Title: Re: 87 hydraulic clutch
Post by: Edahall on July 04, 2011, 12:03:56 am
For hydraulic setups, a lighter clutch pedal can be achieved by the use of a clutch master cylinder of smaller bore diameter or by the use of a slave cylinder of a larger diameter.  However, with a lighter clutch pedal comes a longer stroke.  On my 1990 Suburban, I installed a Jeep CJ5 clutch master cylinder which has a smaller bore and it gave a light clutch pedal feel but it lengthened the stroke about 30%.  A longer stroke makes shifting a bit slower but the light pedal sure is nice in stop and go traffic.  I can drive in Los Angeles CA stop and go traffic for hours towing and it doesn't tire my leg out so much.
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 04, 2011, 10:16:12 am
hey thanks what year cj5 was it?
Title: Re: 87 hydraulic clutch
Post by: Edahall on July 04, 2011, 02:22:39 pm
hey thanks what year cj5 was it?

1989

It fits right in but the rod has to be lengthened.
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 04, 2011, 02:51:43 pm
do you weld a peice to it? or can you use the rod from the original chevy one. i just had to put an ignition switch in the truck today thank God for standard trans it woas stuck in the run position. also there is a grease fitting on the bellhousing is that anything that may help its near the clutchfork
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 04, 2011, 05:42:21 pm
hey did you mean wrangler? i looked up cj5 but they didnt make em that year
Title: Re: 87 hydraulic clutch
Post by: Edahall on July 04, 2011, 06:17:48 pm
hey did you mean wrangler? i looked up cj5 but they didnt make em that year

I should have said 1989 Jeep YJ Wrangler.  The part should look like this.  I welded the Chevy rod to the Jeep master cylinder rod.

(http://info.rockauto.com/getimage/getimage.php?imagekey=1135785&imageurl=http%3A//info.rockauto.com/RhinoPac/M0101.jpg)
Title: Re: 87 hydraulic clutch
Post by: Edahall on July 04, 2011, 06:38:57 pm
Sorry, I left part of the equation out.  I also used a slave cylinder from a 2001 Dodge 3500 truck with the Cummins.  The bore on this slave cylinder is larger than the Chevy (Dodge .906 vs Chevy .8125) which would be responsible for my lighter clutch pedal.  The master cylinder bore on a Chevy is identical to the Jeep 11/16" however, the Jeep has more volume which is needed to run the larger slave cylinder from the Dodge.  Anyways, I hope that this didn't add too much confusion.
Title: Re: 87 hydraulic clutch
Post by: Edahall on July 04, 2011, 06:54:21 pm
Alright, I did some research for you and for your truck, you would be better off to buy a 5/8" clutch master cylinder from Wilwood.  

http://www.amazon.com/Wilwood-260-2636-Master-Cylinder-Girling/dp/B003XVEFHC

You would achieve a very similar pedal feel to mine and not have to change out / retrofit the slave cylinder.

Let me know how it works out when you're finished.

(http://www.lpiracing.com/catalog/260-1304_dwg_340_detail.jpg)
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 04, 2011, 09:47:07 pm
wow thanks a lot!!!!! you did a lot of work on a holiday. i appreciate it very cool
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 04, 2011, 09:53:20 pm
its funny i also just ordered a 5/8" master for a toyota as plan b with a bigger reservoir just in case i like that idea better than changing the slave too but again i appreciate all the work on the 4th of july.
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 17, 2011, 08:34:30 pm
so i went to try my bigger slave cylinder and i went to stop by the auto parts store to grab a couple of what i thought were male flare fittings and parts guy much smarter than me looks at the slave i had and said this is not a threaded fitting its a pressed in plastic fitting ( its pressed in and then a pin gets pushed in next to it to secure it) which is all well and good except what kind of fitting is that and where do i get one and can it go on a steel brake line?
Title: Re: 87 hydraulic clutch
Post by: 1980c10 on July 17, 2011, 11:03:20 pm
I had a similar situation as to what you have now as my slave cylinder is from a '98 chev p/u. I went to the junk yard to get the end of the line and fitting cut it off 8" or so and flared the end to attach it to a brake line. Also the pin I needed ended up being a pretty common roll pin. The line pushes in and is then secured with the roll pin. I can actually rotate mine when it is installed but it doesn't leak at all.
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 18, 2011, 12:01:46 pm
was your slave plastic? it sounds similar and the end is metal and can be put on regular brake line if you flare it? thanks for responding
Title: Re: 87 hydraulic clutch
Post by: 1980c10 on July 18, 2011, 10:11:48 pm
My slave is metal and some of the factory line was plastic but I was able to cut it near the slave where the line was metal then flared an end on the line where I could connect it to a brake line which leads to my clutch cylinder which happens to have a fitting that matches a brake line end.
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 19, 2011, 09:09:37 am
thanks sounds like a good idea
Title: Re: 87 hydraulic clutch
Post by: Edahall on July 19, 2011, 10:23:42 am
I did some checking for you and the stock slave cylinder for your truck is a 13/16".  I'm not sure that going to a 1-1/4" slave cylinder is going to work.  I'm afraid the volume would be too large for a any master cylinder less than 1".  A 5/8" master cylinder would not push that slave cylinder far enough to disengage the clutch.  On the other hand, a slave cylinder on the order of 7/8" or possibly 1" might work.
 
Title: Re: 87 hydraulic clutch
Post by: 1980 gold on July 19, 2011, 10:29:41 pm
i went to try this sunday ( the slave ) and i had to laugh i went to buy a fitting for it turns out its not a regular flare fitting so  i basically canceled that plan  until i either find a fitting that will work may on the other hand order a 1 inch slave it looks like most of them will bolt up the same and have the same dimensions
Title: Re: 87 hydraulic clutch
Post by: 1980c10 on July 19, 2011, 10:52:47 pm
Like I mentioned I got my fitting from the local u-pull-it yard as i couldn't buy one from any local places without buying the whole line.