87 Chevy Clutch issue...

[Caminofeld]

Hey guys, so I had the clutch position switch randomly break in my 87 K5. Not a big deal, but since then my clutch is slipping horrendously. Up until the moment where the switch broke, the clutch had good hold and didn't slip at all. I replaced the switch last night, and the clutch is still slipping. I'm not sure where to start with diagnosing the problem. Any help or suggestions would be greatly appreciated. Thanks!

Oh, and this IS 3 wheeler related, because I sometimes use it to haul my trikes:)

[trike savior]

first question is mechanical or hydraulic clutch linkage. if its mechanical I have seen many different things cause that like broken pivots and engine mounts. if its hydraulic I would check the mounting of the master and slave. also check the clutch fork for cracks or breaks. I am assuming it was all assembled/ installed properly. If everything is good with the clutch it should be engaged all the time, that is why I am assuming you have linkage bound up somewhere holding clutch disengaged. when under the truck you should be able to move clutch fork a bit by hand and feel some play. if it feels solid then it is stuck somewhere. also need to look at throwout bearing but that usually just makes noise or wont disengage clutch.

[Caminofeld]

Thanks for the reply. It is a hydraulic clutch and I'm going to get into it tomorrow and check everything you told me. It's just weird that the pedal position switch breaking caused this. When it rains it pours I guess. Thanks again and I'll keep you posted.

[Caminofeld]

My only other thought is that not having the tension of the position switch caused the clutch to auto-adjust to an improper depth and when it initially slipped I glazed the friction plate...so now that it has auto-adjusted back to normal after replacing the part the clutch is fried and needs to be replaced...I really hope not though.

[El Camexican]

I don’t know your 87, but on the off chance they are the same my 89 had a master and two slave cylinders go in a short span of time and I learned the hard way that you need to have the front of the truck raised a bit to bleed the slave, or you’ll never get all the air out.

[barnett468]

Hello Caminofeld;


Please explain EXACTLY what a clutch position switch is.

Are you able to set the pedal height electronically to fit your height/leg length etc.?

There might be a "freeplay/preload" adjustment on the linkage somewhere. If so, I would set the free play 1/2" of pedal movement. If your Blazer has a diaphragm clutch the trans might grind or not go into gear when the pedal is fully depressed. If it does, run it hard, preferably on an uphill, and if it slips it is NOT caused by your switch.

If you need a clutch kit and don't have much money you can buy an oem kit from rock auto. the oem type brands are LUK and SACHS. Valeo is ok. I would not run an EXEDY.

I run Mcleods or Centerforce but they are pricey. Most of the non brand name kits you see are from china and will not work.

[Caminofeld]

Thanks guys. A clutch position switch is just a rod that attaches from clutch pedal to a switch under the dash. From what I understand, it's sole purpose is to not allow the vehicle to start unless the clutch is depressed (preventing lurching forward in gear). In my vehicle, the switch/rod holds the clutch pedal further out than when it's not connected...which is why I think that after it broke and the clutch pedal sank than the clutch auto-adjusted to an improper depth. From what I know there's no real correlation other than that between the switch and a slipping clutch...which is why I'm so baffled that they happened simultaneously. I may just have to break down and go to a mechanic.

[barnett468]

ok, thanks fur the info. a photo of the switch and rod would help however the switch has nothing to do with yiur clutch slipping even though you say your pedal is now lower since it broke. all this means is that the switch supports the pedal to some degree which s a bit unusual bit it is what it is.

if you need a mechanic i suggest you get prices from smaller shops. make sure they tell you what the price includes. if the clutch is wasted you need the flywheel resurfaced a new pressure plate and new disc.

a cheap chinese disc will fail quickly and might chatter when the clutch is released. a good disc is extremely important.

prices for the same work and brand of parts can VARY up to around $300.00 from shop to shop. yes its nuts.

look at the old parts and the new parts and the flywheel to insure they are doing what they should be.

some shops like to buy chinese parts then charge you prices for us made parts.

some shops let you supply your own parts but then charge you more for labor and might not give ylou a warranty because you did not use their brand of parts. it can be a PITA.

Install a new non chinese throwout bearing while you are at it.

rebuilt pressure plates can be ok but do not buy a rebuilt disc. they do not replace CK AUTO!

The marcell disc when they rebuild them therefore some rebuilt discs will chatter when taking off from a stop guaranteed.

ROCK AUTO!

[trike savior]

i was thinking along the same lines of elcamexican but air in the system would make you unable to disengage clutch and you are saying it is disengaged (slipping) all the time. that's why i am saying you have to have something holding pressure on clutch fork somewhere.

As i said a clutch wants to always be engaged. the master and slave and everything else give you the ability to disengage, so something there has to be applying pressure to it. Now it is possible for the spring on the pressure plate to break causing it to slip. but that usually only happens on clutches with a lot of miles.

i highly doubt you smoked the new clutch already. Im sure it has to be something not allowing it to engage.

Being out of adjustment is a good possibility. when adjusting it, you ideally want the first 1" of clutch pedal travel to do nothing. having it disengage as soon as the pedal is touched is not good and can cause premature failure.

if you can see that the throwout bearing is not contacting the clutch fingers (remove slave if you have to) and the clutch still does not act engaged all the time, then there is a problem with the clutch assembly itself

[just ben]

does it slip in all gears or just the higher gears? I had an s-10 That the slave cylinder went bad and didn't release completely which glazed the clutch disk so it still slipped after replacing the slave. Since it was a low mileage clutch I just replaced the disk and the throw out bearing. The switch like you said is just to start it and has no effect on the function of the clutch. My guess would be a bad slave or just a worn clutch. You didn't mention how many mile are on the clutch?

[El Camexican]

In case there was some doubt I don’t think your switch has anything to do with this. It is likely a situation where to things went wrong at the same time. My comment on the slave was only as a heads up if you end up needing to bleed it. Let us know what happens.

[Caminofeld]

Thanks for all the advice guys...I'm gonna make her a Springtime garage project because mechanics are quite pricey these days. Ordering the parts soon.

[Caminofeld]

I am going to start by replacing the slave, master, and line (not that I think it will fix the problem, just figured if I'm gonna keep the beast around for awhile it would be a good thing to replace). I'll bench bleed the system and put it in hopefully before the next blizzard:cry:

[barnett468]

I am going to start by replacing the slave, master, and line (not that I think it will fix the problem, just figured if I'm gonna keep the beast around for awhile it would be a good thing to replace). I'll bench bleed the system and put it in hopefully before the next blizzard:cry:Bad hydraulics like the slave will NOT cause it to slip but can prevent it from disengaging fully or staying disengaged if the pedal is held down.