JStone Posted October 20, 2021 Share Posted October 20, 2021 Hey dudes, I need some advice on what to do in this situation. Driving through the city yesterday and my clutch went from what I consider “long” to an extremely short engagement point..extremely short. Though it still let me shift into gears to make it home, I don’t plan on driving it. Fluid is full but dark and now the pedal is almost all play with the spring being the only thing giving tension. I haven’t done any work on it lately, or had any sort of indication it was starting to fail. I guess besides Reverse was a Lil bit crunchy. I’ll bleed it this afternoon and see what that does. I appreciate any bit of advice! Link to comment Share on other sites More sharing options...
Eagle Posted October 20, 2021 Share Posted October 20, 2021 There are three things that could have spring a leak -- the master cylinder, the slave cylinder, or the rubber hose that connects the two. Link to comment Share on other sites More sharing options...
JStone Posted October 20, 2021 Author Share Posted October 20, 2021 41 minutes ago, Eagle said: There are three things that could have spring a leak -- the master cylinder, the slave cylinder, or the rubber hose that connects the two. Even though the fluid reservoir is full? I seen a little bit of fluid inside the fire wall by the pedal but not any signs of excessive fluid or corroding paint like that. If I learned correct from my research that which breaches the firewall is the master cylinder? Seems pretty replaceable. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 20, 2021 Share Posted October 20, 2021 Let’s start here. Has anything been replaced in terms of from clutch master to slave? Is it internal or external? Link to comment Share on other sites More sharing options...
JStone Posted October 20, 2021 Author Share Posted October 20, 2021 2 hours ago, eaglescout526 said: Let’s start here. Has anything been replaced in terms of from clutch master to slave? Is it internal or external? I have not replaced anything, and to be honest I'm not sure the difference between internal or external. From the clutch pedal, the rod goes through the firewall into the fill reservoir, then has the connection hose going down into the transmission case. Ive looked over all of it and havent found any excessive fluid leaking or anything saying fix me. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 20, 2021 Share Posted October 20, 2021 Ah ok. The clutch slave cylinder can be external(outside bell house) or internal(inside bell and an all in one assembly). External is the superior set up as it usually works the best but the internals with time can fail sooner than an external set up would. But since nothing has been replaced, it wouldn’t hurt to give a refresh and possibly rebuild the master cylinder. Link to comment Share on other sites More sharing options...
gogmorgo Posted October 20, 2021 Share Posted October 20, 2021 External slave would have a little piston on the side of the bellhousing that the line goes into, secured by a couple studs. Internal just has the line going into a plug in the bellhousing. If you post up a picture of the spot where the clutch line goes into the bellhousing we can make a positive ID for you. Internal is simpler and usually more reliable due to less moving parts, assuming you're buying good quality parts, but the downside is it requires pulling the trans to change it out, compared to an external slave that's just three fasteners. If it started leaking the level in the reservoir would in theory drop, but if there's some gunk in the bottom of the reservoir it's possible it's plugged and the master cylinder isn't sucking the fluid down. It's also possible the master cylinder has a blown seal internally and isn't pushing the slave cylinder, just bypassing it. Any fluid leaking out of the clutch is excessive. Fluid going out means air is coming in, and any air in the system will need compressed before the slave cylinder will move. When it fails, an internal slave cylinder will leak brake fluid out of the dust shield at the bottom of the bellhousing. This might be hard to detect if there's any engine oil leaks, but if you pull the inspection cover off, the leak may be more obvious. Link to comment Share on other sites More sharing options...
Eagle Posted October 21, 2021 Share Posted October 21, 2021 10 hours ago, JStone said: Even though the fluid reservoir is full? I seen a little bit of fluid inside the fire wall by the pedal but not any signs of excessive fluid or corroding paint like that. If I learned correct from my research that which breaches the firewall is the master cylinder? Seems pretty replaceable. If the hose from the master cylinder to the slave cylinder blew, there would be fluid loss. The master cylinder and the slave cylinder each have a piston inside with a rubber seal. If the lip of the seal goes bad, the piston can move without pushing fluid, so you wouldn't see a loss of fluid in the reservoir. The piston just slides back and forth without doing anything. Also -- inspect your fuse panel under the dashboard (over the driver's left foot) carefully. If the master cylinder goes bad, it can allow brake/clutch fluid to weep onto the fuse panel, and that will destroy the contacts VERY quickly. The fact that you see a "little bit" of fluid is a bad sign. There's probably more that you can't see, on the back side of the fuse panel board. That's a clue that the master cylinder has failed, and also that you need to remove the fuse panel and flush all the brake fluid off it before it's too late. Link to comment Share on other sites More sharing options...
Pete M Posted October 21, 2021 Share Posted October 21, 2021 1990 would be internal. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 21, 2021 Share Posted October 21, 2021 What is "not excessive fluid leakage? This is a good reason to change out your clutch fluid every once in a while......even if you suck the old fluid from the clutch master and add new a few times. Link to comment Share on other sites More sharing options...
JStone Posted October 21, 2021 Author Share Posted October 21, 2021 15 hours ago, gogmorgo said: External slave would have a little piston on the side of the bellhousing that the line goes into, secured by a couple studs. Internal just has the line going into a plug in the bellhousing. If you post up a picture of the spot where the clutch line goes into the bellhousing we can make a positive ID for you. Internal is simpler and usually more reliable due to less moving parts, assuming you're buying good quality parts, but the downside is it requires pulling the trans to change it out, compared to an external slave that's just three fasteners. If it started leaking the level in the reservoir would in theory drop, but if there's some gunk in the bottom of the reservoir it's possible it's plugged and the master cylinder isn't sucking the fluid down. It's also possible the master cylinder has a blown seal internally and isn't pushing the slave cylinder, just bypassing it. Any fluid leaking out of the clutch is excessive. Fluid going out means air is coming in, and any air in the system will need compressed before the slave cylinder will move. When it fails, an internal slave cylinder will leak brake fluid out of the dust shield at the bottom of the bellhousing. This might be hard to detect if there's any engine oil leaks, but if you pull the inspection cover off, the leak may be more obvious. Thank you all for the help and insight, it has all been greatly used. It is definitely an Internal slave cylinder, and unfortunately I don't have the resources to pull the trans and change that cylinder. Ive only leaked about a table spoon of oil on the inside of fire wall and fusebox, cleaned what little there was. Luckily is was pretty fresh and did no damage. I just don't want to swap out parts that may or may not work. I think ill just have it towed to a place here in salt lake, but learning about the clutch has been fun, i hope on not making it my nightmate! Link to comment Share on other sites More sharing options...
Pete M Posted October 21, 2021 Share Posted October 21, 2021 is it 2wd? sounds like a great time to invest in those resources. only takes basic hand tools (if the truck isn't all rusty) and maybe a helper to assist with dropping/installing the trans. and if you want to swap out the master first to see if it had an internal failure, that's even easier! Link to comment Share on other sites More sharing options...
JStone Posted October 21, 2021 Author Share Posted October 21, 2021 Yeah it is a RWD. Pete do you have a recommendation for these parts? I have read back and forth on different brands but I haven't found any links. I also read that there is an upgrade material to use for the master cyl? Link to comment Share on other sites More sharing options...
cruiser54 Posted October 21, 2021 Share Posted October 21, 2021 What are you gonna replace? Link to comment Share on other sites More sharing options...
jamcomanche Posted October 22, 2021 Share Posted October 22, 2021 13 hours ago, JStone said: Thank you all for the help and insight, it has all been greatly used. It is definitely an Internal slave cylinder, and unfortunately I don't have the resources to pull the trans and change that cylinder. Ive only leaked about a table spoon of oil on the inside of fire wall and fusebox, cleaned what little there was. Luckily is was pretty fresh and did no damage. I just don't want to swap out parts that may or may not work. I think ill just have it towed to a place here in salt lake, but learning about the clutch has been fun, i hope on not making it my nightmate! Have you tried bleeding the line? BTW, If you have any fluid leaking inside the firewall at all, my advice is to go ahead and replace the master cylinder. I had a problem with a slow leak in mine, slow enough that it took a while for the reservoir to go low. After some time though I eventually started seeing puddles on the floor mat. Not to mention it drips right onto the back of the fuse panel and creeps into every terminal. Replacing the master cylinder is really not bad, and you'll have a chance to bleed the lines which may end up being exactly what you need to do. You can do it fairly quickly if you have somebody to help you manage the pedal while you bleed the line underneath. Your bleeder is on the opposite side of the tranny from where the line from the master cylinder goes into it. If you don't have somebody to help with bleeding, you can do what I've done in the past with brakes and use a board just long enough to depress the pedal and wedge it in front of the seat xD. It makes the process take a lot longer though. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 22, 2021 Share Posted October 22, 2021 Replace the clutch master cylinder. Use DOT 4 fluid. It ain't gonna get better on it's own. As far as parts brands go, who knows? It's all imported anyway. Anywhere but china is best. Link to comment Share on other sites More sharing options...
Eagle Posted October 22, 2021 Share Posted October 22, 2021 9 hours ago, cruiser54 said: Replace the clutch master cylinder. Use DOT 4 fluid. It ain't gonna get better on it's own. I agree on replacing the clutch master cylinder. However, I recommend using DOT-5 silicone brake fluid. It's non-hygroscopic, so it won't attract moisture vapor and, more important, it isn't corrosive. That means if it weeps onto the fuse panel it won't destroy it. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 22, 2021 Share Posted October 22, 2021 Ah, for the fuse panel.. Good to know. Link to comment Share on other sites More sharing options...
JStone Posted October 22, 2021 Author Share Posted October 22, 2021 On 10/21/2021 at 3:56 PM, cruiser54 said: What are you gonna replace? Replaced the master cylinder. Got some real nasty black oil out and threw in some fresh. I didn’t see the recommendation for dot 5 until now. But got it finished late last night and the clutch is working like a champ. Thank y’all for the insight and the confidence to just get er dunn. Link to comment Share on other sites More sharing options...
eaglescout526 Posted October 22, 2021 Share Posted October 22, 2021 If your master is still the original nabco one, hang on to it and tear it apart. Those are the factory ones and are much better and worth a rebuild if the cylinder inside is still in good shape. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 22, 2021 Share Posted October 22, 2021 87 probably a Girling....yuck. Link to comment Share on other sites More sharing options...
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