Will not shift

[dindin]

Hi everyone, Great information here

I and new here, but I have owned my 75 Cosworth for 30 years now, It has about 40,000 miles..the other day I had a problem where I could not shift into gear when backing out of a parking spot,when going into reverse it felt like the clutch was not pressed in, just a wicked gind. It also would not go into any other gear but stuck in neutral.

I finally got it to shift by shutting off the engine and putting the car into first gear then starting the car up and driving it away, but it feels very hard to shift through the gears now, like I am powershifting, I notice if im on a hill and press the clutch I cannot move the shifter so easily, it feels as if the clutch is disengaging from the engine but something is holding the shifter, if the car is flat with parking brake on it moves very easily through gears.

I allways had a slight grind going into reverse and had to be carefull, but this last episode was much worse.

So shifter seems good, but why would the clutch disengage the engine but still not allow me to shift into any gears??

Thanks for reading hope its not too confusing..

Al

[gerbsinmd]

Sounds like you could have a one or two things going on. You might need to rebuild your shifter linkages, including the rubber grommets where it bolts to the body, AND/OR the clutch is not completely disengaging. This one could be more troublesome, either the cable is failing, or the cable has pulled through the firewall.

[cjbiagi]

Could be a number of things but starting with the easiest would be to check the clutch adjustment and cable condition. Checking for firewall flex should also be high on the priority list as this has affected some cars. Then start looking at the other items mentioned, the shifter grommets could be worn as well as the grommets that hold the shifter to the shifter mounting plate. All of these should be checked BEFORE going through the shifter rod adjustments. Any of these things could be a issue and causing your problem, this all assumes the problem is not in the trans itself. Replacing the trans fluid is also a good idea if it hasn't been done in years. Here's a write up on adjusting the cable and clutch fork pivot. If you need any of the hard to find grommets for the shift linkage or shifter mounting plate let me know as I should be able to provide them. There could also be a problem with the pilot bearing on the end of the crank if it is binding on the input shaft but lets hope it's something easy. Any other questions, feel free to ask....

Ok, here goes. What many people do on these cars is mistakenly adjust the nut on the end of the cable to get there pedal freeplay. This happens because some people don't even know about the clutch ball pivot on the top right side of the bellhousing.
What you want to do is make sure that the clutch fork is pulled all the way to the rear of the car. The return spring should accomplish this, but just make sure it is all the way back. Now you want to adjust the cable by turning the nut at the clutch fork to remove all the slack. You must also make sure that the pedal is all the way up, it helps to have someone pull the pedal up against the rubber bump stop while you adjust the nut to remove any slack in the cable. What you are trying to accomplish is, clutch fork all the way back, pedal all the way up, no slack in the cable. Once this is done now you can adjust the pivot ball on top of the bellhousing. The best way to do it is to actually measure the gap between the clutch disc and the flywheel when the pedal is depressed to the floor. For a diaphram clutch you should have about .030. The only problem is there is no easy way to measure this without an inspection hole in the bottom of the bellhousing. I drilled a small hole in mine, big enough to insert my feeler gauge. It has to be drilled at the point where the disc mates with the flywheel. At this point you loosen the large locknut on the adjusting screw and turn the pivot ball to get the proper gap with the pedal depressed, then lock down the locknut. Since most folks don't have any way of measuring this gap, the more common method of adjusting the pivot ball to result in 1" of pedal freelplay will also work fine. The important thing to remember is that you want the freeplay to be the result of a gap between the throwout bearing and the pressure plate fingers. Having freeplay as a result of a loose cable is not what you want. That's why you want to make sure that there is no slack in the cable to throw off your freeplay measurement. With no slack in the cable, the clutch fork will begin moving immediately when you start to depress the pedal. The clutch fork and throwout bearing will also begin to move immediately, taking up the small gap between the throwout bearing and pressure plate fingers (which gives you your pedal freeplay) and all will work fine. With the cable and pivot ball properly adjusted the throwout bearing will not be in contact with the pressure plate once the pedal is up and there will be no chance of clutch slippage since the pressure plate will be allowed to fully engage. You can fine tune the stud to suit your preference but this puts you very close to where it should be. The important thing is to not have any slack in the cable when you are done, that is just wasted motion and it does not accomplish freeplay where you need it. Different brands of pressure plates and throwout bearings will effect where the stud needs to be. Some clutch assemblies are a little thicker and not all "short" throwout bearings are the same length. Hope this makes sense, if not ask me again!
*** I am adding this simple step by step process which summarizes the above.

1) Have someone pull the clutch pedal against the rubber bump stop.
2) pull clutch fork all the way toward the rear of the bellhousing
3) adjust cable nut to remove any slack
4) Loosen nut on pivot ball stud
5) adjust pivot stud to obtain 3/4" - 1" freeplay at clutch pedal.
6) recheck cable to make sure there is no slack

Clyde

[dindin]

Thanks for the replys,

As far as the firewall flex, the cable is not pulled through it looks fine, unless its pulling the firewall itself??

I will check for worn grommets also,

I never did change the tranny oil though, can you recommend a fluid type and is it difficult??

I think (know) the cable adjustment is off, I put a new cable about 10 years ago and just cinched up the slack at the nut, also I need to push pretty hard on the clutch petal also..any way to make the clutch lighter??

Thanks
Al

[cosvega76]

Welcome, Al!

For the transmission, assuming it's a Saginaw 4-speed, use a regular gear lube, like 75W90. To drain the old lube you can usually remove the lowest bolt mounting the tailshaft housing to the main housing, as there isn't a drain plug on those transmissions. Use a suction gun to refill the trans, up to the level of the fill plug.

As far as the stiff pedal, the proper clutch adjustment (as Clyde described) will certainly help. A misadjusted clutch fork messes with the geometry and makes it hard to depress. If it is still stiff, lubricating the cable may help. Clyde also has a good procedure for that.


Chuck

[cjbiagi]

If your cable is 10 years old and is stiff I would highly recommend replacing it with a new one. I have found that lubricating the cable helps tremendously with the clutch pedal effort. It's easy enough to pull the cable out of the firewall and get a small oil can and squirt some oil down the sheath. I have not determined the best oil to use but at this point I would suggest some good synthetic oil. Also, if your cable runs close to the exhaust it's a good idea to insulate the cable from the heat as there is a teflon liner inside that can melt and bind on the cable. If you need a cable let me know, the cosworth one is a bit longer than some others. The proper clutch cable and ball stud adjustment should help with the clutch fork angle and give you the best results, follow the write up I posted and you should be in good shape as far as the cable and fork go. If you still have a problem then you are going to have to look deeper into the shift linkage adjustments, grommets etc. In order to check the firewall for flex you need someone to depress the clutch pedal as you observe the firewall, I can almost gaurantee it is flexing to some degree. cjbiagi@yahoo.com

[marco_1978_spyder]

Bad Clutch Fork? Mine was acting similar when my clutch disc was going bad (shattered) and actually lost a piece of metal that lodged just right into the pressure plate springs causing the clutch to act like your's.

[Monza Harry]

Al (& Clyde) I had a thought, let me check a few facts first. I am assuming that you haven't driven the car in awhile, (by the low mileage) is it possible that your pilot shaft has perhaps picked up a little "flash rust" from sitting and that is causing the input shaft to spin just enough to make shifting difficult? For your car Clyde maybe the shaft was on the big side and your bushing was on the small side for your hard shift scenario (going into reverse?) you said yours has done it from New? Just an Idea! Harry