Ford Mustang Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
9,239 Posts
Discussion Starter · #1 ·
I recently read a great article/interview in one of the British hard core race magazines with a tech guy from AP Racing (they make brakes and clutches for some serious race car stuff) where they talked about break in on clutches and how important it is. The AP guy was saying that a 500hp clutch not broken in correctly will get snatchy and could loose as much as 125hp in holding ability. But on the flip side if broken in just right that 500hp rating will go up over 600hp and it will drive very close to stock. I took what I learned from the article and what I have learned from bedding in HUNDREDS of sets of brake pads (very similar to clutches) and came up with a clutch break in procedure and tried it out on my new clutch this past spring. It worked great! My last clutch, the same kind I just put in was horrible compared to the new one. My last clutch went in the car and then straight on the dyno. I’ve bedded in a few like outlined below now and have given the bedding instructions to a few other people. So far it has worked great every time. I thought I would pass it on.

Before you install the clutch scuff the pressure plate and flywheel with ScotchBrite and brakekleen for a fresh surface. This is to remove any clutch material from the previous disc if used and any chemicals or worse case lubricants, etc if dealing with a new flywheel and/or pressure plate. You don’t need to go crazy, just scuff it up. DON’T USE STEEL WOOL!

The clutch break in is easy, just time consuming. The theory behind it is that you want to transfer some of the clutch discs friction material to the pressure plate and flywheel right away. Doing so will increase the clamping force considerably. What you don’t want to do it transfer the bonding agents (glue) in the clutch disc to the pressure plate and flywheel. That will reduce clamping forces a lot. The bonding agents “leech” out of the clutch disc when they are new and subjected too much heat, too fast. If the bonding agents leech out they will “glaze” the clutch and leave a layer, not always even on the pressure plate and flywheel.

So what you want to do is “bed” the clutch in without introducing much heat very quickly. The best way I have found to do this is to “put, put, put” around the neighborhood. Go one block, stop at a stop sign. Go another block, stop at a stop sign, repeat, repeat, repeat. Pull away from the stop signs like an old lady. Remember the key is very little heat so you don’t want to slip the clutch much and you don’t want to load it once engaged (NO hard acceleration). Its easy to tell when things are bedded with brake pads because you can feel it in the “bite” but no so much with the clutch. But its there. You will feel it start to get more aggressive at some point. That is when you have transferred that friction material. I didn’t count my last time out but it took somewhere between 20-40 stop signs. Once it is bedded in park it until 100% cooled down. The cooling process is part of the process. The bonding agents in the disc go though their last chemical change the first time you get heat in it, and that change is not completed till fully cooled.

Once cooled you are ready for normal use. It still wouldn’t hurt to put 50mi or so on the clutch driving “normal” (I.E., slow and boring) though. So if have the time/patience it sure wouldn’t hurt.

I’ve used the above method on a Spec Stage III+, which are known to be snatchy and without a lot of feel and it behaves just like a stock clutch aside from the pedal taking more effort. I can pull away from a stop without even touching the gas the engagement is so smooth. There was no way that was going to happen with the previous clutch (a Spec Stage III+) that was not bedded in properly.

Hope this helps.:bigthumbsup
 

·
Registered
Joined
·
766 Posts
Well,,,,That puts to BED any questions about how to do that.........:gringreen
 

·
Registered
Joined
·
1,452 Posts
Makes a lot of sense. Always better to break in something without braking it. Excessive heat is the enemy of new brakes, clutches, transmissions and engines.

Frank
 

·
Registered
Joined
·
9,239 Posts
Discussion Starter · #4 ·
Well,,,,That puts to BED any questions about how to do that.........:gringreen
Bada, BUMP! He’s here all week ladies and gentlemen! Don’t forget to tip your waitress……try the veal. I'm Pomeo Davis, "The Man Of The Hour".:hihi:
 

·
Registered
Joined
·
621 Posts
Hey everyone, I just thought I would chime in :smilie

I just put a Spec stage 2+ clutch in on Tuesday and got some clutch BEDDING instructions from Sqidd and I have to tell you that I am very pleased with the results :bigthumbsup

Although it was very hard to keep my foot off of the throttle, I drove the car like a grandma would.

Apparently I did it properly because the clutch feels GREAT !!! grips like crazy and feels fantastic in the city.

My car is a daily driver and I didnt want that on-off clutch feel and was skeptical about getting this clutch but having talked to Sqidd I felt much better about it.

Glad I took his advice, Thanks again dude !!!! :yelpleased:
 
1 - 6 of 6 Posts
Top