outlander
NAXJA Forum User
- Location
- Columbus,Ohio
I heard somewhere that the flywheel on a 89 cherokee w/4.0 should'nt be resurfaced.Is this true?
-
Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.
flywheel resurface?
- Thread starter outlander
- Start date
Rev Den
NAXJA Forum User
- Location
- Plainfield, IL
Yup. Just scuff it.
Rev
Rev
outlander
NAXJA Forum User
- Location
- Columbus,Ohio
Ok disregard this thread.I should have searched first.
Sorry.
Sorry.
5-90
NAXJA Forum User
- Location
- Hammerspace
Partially correct. If removal of material is required for resurfacing a flywheel, the mounting pad for the clutch cover should be "shaved" by a like amount to keep clutch engagement consistent - if the clutch surface much be turned down by .010", the area where the clutch cover mates and bolts down should also be shaved by .010". Failure to do so can result in weak clutch and clutch burning.
5-90
5-90
SteveT
NAXJA Forum User
- Location
- Aurora, CO
5-90
Do you mean have the flywheel machined all the way out to the ring gear, or machine the mount pads on the pressure plate assembly?
Steve
Do you mean have the flywheel machined all the way out to the ring gear, or machine the mount pads on the pressure plate assembly?
Steve
5-90
NAXJA Forum User
- Location
- Hammerspace
All material removed is removed from the flywheel, since it has the most to work with (and it's already set up after surfacing anyhow.)
The cover assembly usually has a stamped sheet housing - taking more than .005-.010" off of something like that is just asking for trouble - while taking that much off a casting is usually considered a "clean-up pass."
Anyhow, the idea is to preserve the relative positions of the parts as mounted. If you are considering having a flywheel resurfaced, ask them how they do the job. I've got one shop out here that does it right - Superior Friction on North Tenth.
It takes a little digging to find good shops, but they're worth the effort. Even so, I only get parts (and do all the rest of the work myself.)
5-90
The cover assembly usually has a stamped sheet housing - taking more than .005-.010" off of something like that is just asking for trouble - while taking that much off a casting is usually considered a "clean-up pass."
Anyhow, the idea is to preserve the relative positions of the parts as mounted. If you are considering having a flywheel resurfaced, ask them how they do the job. I've got one shop out here that does it right - Superior Friction on North Tenth.
It takes a little digging to find good shops, but they're worth the effort. Even so, I only get parts (and do all the rest of the work myself.)
5-90
- Location
- Terra Firma
The factory service manual says NOT to resurface the flywheel.
Ask Kejtar what happens when you ignore this advisory.
Ask Kejtar what happens when you ignore this advisory.
outlander
NAXJA Forum User
- Location
- Columbus,Ohio
That's what I've heard also.But what he is saying sorta makes sense,though.Eagle said:
I think a call to a certified jeep service center is in order to clear this up once and for all.
Last edited:
outlander
NAXJA Forum User
- Location
- Columbus,Ohio
Hopefully that is how it's supposed to be done because that's how napa did mine(all the way out to the ring gear)SteveT said:
old_man
NAXJA Forum User
- Location
- Loveland, Colorado
OK, here is the skinny on why the FSM says not to mill the flywheel. It isn't because of any surface issues. It is because of the non adjustability of the master/slave cylinder. It doesn't have the extra capacity to handle the difference. If you shim the slave cylinder by the same amount (internal slave), you will be fine. I went with a Howes master cylinder with a .875 bore instead of the .750 bore on a stocker.
5-90
NAXJA Forum User
- Location
- Hammerspace
Yep - but not all flywheels have the clutch surface and the mounting surface on the same plane - that's why I qualified my statement. It would just take an extra measurement to set the cut for the mounting surface.
Some flywheels don't do well when resurfaced, and a competent machinist can tell you if this is so. As I recall, there are some "dual-mass" flywheels that are like "composite" brake rotors - these tend to fail drastically when spun and a cutting tool applied.
I wouldn't consider it an absolute that the flywheel cannot be machined - it's something I'll have to look into and experiment with one of these days. Nothing is impossible - some things are just damned difficult...
5-90
Some flywheels don't do well when resurfaced, and a competent machinist can tell you if this is so. As I recall, there are some "dual-mass" flywheels that are like "composite" brake rotors - these tend to fail drastically when spun and a cutting tool applied.
I wouldn't consider it an absolute that the flywheel cannot be machined - it's something I'll have to look into and experiment with one of these days. Nothing is impossible - some things are just damned difficult...
5-90
Rev Den
NAXJA Forum User
- Location
- Plainfield, IL
Unless the flywheel is damaged the is NO REASON to cut it. If its damaged...replace it.
Geeze....simple.
Rev
Geeze....simple.
Rev
5-90
NAXJA Forum User
- Location
- Hammerspace
Y'know, there is that, and it's usually what I prefer to do anyhow...
I was just trying to answer the question as posed - and see if an option for a "quickie" repair or a "back to the real shop" or "keeping going for a week while the new part shows up" can be done...
You should know me better than that by now... :wave:
5-90
I was just trying to answer the question as posed - and see if an option for a "quickie" repair or a "back to the real shop" or "keeping going for a week while the new part shows up" can be done...
You should know me better than that by now... :wave:
5-90
Rev Den
NAXJA Forum User
- Location
- Plainfield, IL
5-90.
I in no way ment any hostility or frustration toward you personnaly, in re-reading my post it seems that I did....I apoligize for that.
Rev
I in no way ment any hostility or frustration toward you personnaly, in re-reading my post it seems that I did....I apoligize for that.
Rev
Bender
NAXJA Forum User
- Location
- Cambridge, Ontario
I'd say given the flywheel is of a style which will handle being machined I'd compared it's thickness to a new flywheel of the same type to see if it has been machined before. If it has not I see no problem machining it to clean it up and using it as is.
I think the FSM recommendations are conservative and they want to save themselves from the potential of a flywheel being machined 2..3..4 times to a point where the slave and master will no longer make up the difference.
Taking 0.010" off a flywheel that has never been machined before will only add .010" of stroke to the slave cylinder and approx 1/16" to 3/32" of stroke to the clutch master. Both of these compoents have enough reserve capacity to make up this difference. I can see it being a problem however if the flywheel has been machined numerous times but not if it's only been machined once.
I think the FSM recommendations are conservative and they want to save themselves from the potential of a flywheel being machined 2..3..4 times to a point where the slave and master will no longer make up the difference.
Taking 0.010" off a flywheel that has never been machined before will only add .010" of stroke to the slave cylinder and approx 1/16" to 3/32" of stroke to the clutch master. Both of these compoents have enough reserve capacity to make up this difference. I can see it being a problem however if the flywheel has been machined numerous times but not if it's only been machined once.
5-90
NAXJA Forum User
- Location
- Hammerspace
Rev Den said:
No ache - I had to start explaining my answers to nearly everything starting in middle school! I'm used to it - and most people can't read me anyhow...
Bender - one thing I like about the shop that I use for these things is that he will stamp a code near the bolt holes - it's the number of passes the flywheel has had to clean it up, and how much was taken off. I started using him for forklift work (where a flywheel can run a couple thousand pretty easily...) and that was a feature of his work that I liked. He duplicates the stamping front and rear - just in case it goes to someone else (if the marks don't match, he won't do the job - doesn't know what's involved anymore.)
I'm seriously picky when it comes to things like this - that's why I use the shops I do (they've passed my own tests - which are usually harder than anyone else's.) All my shops are members in good standing of "The Picky Bastard's Club" - meaning that they're at least as much a perfectionist as myself. I like parts I can install and forget - I've never needed their warranty!
5-90
Mind if I butt in...
My flywheel was resurfaced without my knowledge, at least was done without my permission, during the first clutch job some years back. Never imagined that it caused any problems ...
That replacement clutch worked okay, with some occasional chatter, for about 5 years and last summer I changed everything again. Here's the catch:
For some reason, say at start up in the morning, I get about 10-20 real easy shifts before things get stiff. Say after about a half hour of driving, reverse is kind of an issue. After an hour, reverse isn't an option. Normally I stop the engine to shift first.
Since this is a thread about resurfacing flywheels, I will not reply to anyone who asks me anything about bleeding air out of the system.
My flywheel was resurfaced without my knowledge, at least was done without my permission, during the first clutch job some years back. Never imagined that it caused any problems ...
That replacement clutch worked okay, with some occasional chatter, for about 5 years and last summer I changed everything again. Here's the catch:
For some reason, say at start up in the morning, I get about 10-20 real easy shifts before things get stiff. Say after about a half hour of driving, reverse is kind of an issue. After an hour, reverse isn't an option. Normally I stop the engine to shift first.
Since this is a thread about resurfacing flywheels, I will not reply to anyone who asks me anything about bleeding air out of the system.
5-90
NAXJA Forum User
- Location
- Hammerspace
"Did you bleed the system?"
Sorry - couldn't resist. Sometimes ya just set yerself up as a target...
Seriously tho - was the flywheel resurfaced totally, or just on the friction area? Any clutch oddities will probably show up in reverse before anything else, because reverse is not synchronised and uses straight-cut gear teeth, rather than helical (which is why reverse has that little "whine" at higher speeds.)
As far as why things would go goofy after changing the clutch, I'd have to know more before I could even try to guess...
5-90
Sorry - couldn't resist. Sometimes ya just set yerself up as a target...
Seriously tho - was the flywheel resurfaced totally, or just on the friction area? Any clutch oddities will probably show up in reverse before anything else, because reverse is not synchronised and uses straight-cut gear teeth, rather than helical (which is why reverse has that little "whine" at higher speeds.)
As far as why things would go goofy after changing the clutch, I'd have to know more before I could even try to guess...
5-90
Bender
NAXJA Forum User
- Location
- Cambridge, Ontario
I've seen a couple pressure plates out of the box that had really bad machining marks on them. Looked like the mill was set way to fast with a dull bit as you could feel the grooves with your fingers easily. I've never installed one...just had the parts guy give me a new one as I didn't want to risk it.
