Afternoon all, I have clutch slip in 4th ... maybe lower gears but they seem OK driving earlier. 

We suffered a blown Slave cylinder about 8 weeks back and changed the clutch, bearing, slave, master and the two gear cables. All went together nice enough but today I noticed a nasty clutch slip in 4th under heavier acceleration.

Any ideas folks? Reassembly was clean but something doesn't seem right. Any input or suggestions very welcome. Thanks in advance

P.S it's a 18 Zetec petrol Mk1 estate

air in the system maybe

14 hours ago, dezwez said:

air in the system maybe

Good call dezwez ..... new to the world of Mk 1 Focuses after many years on early 90's 106's and Micra's .... I forget there's a difference. Yes will give that a look over. Appreciated. Will let you know.

I had a clutch failure as you described some years ago when on holiday.

it was changed by a local garage and I asked him to keep the parts for my inspection.

Much to my suprise there was adequate friction material on the old clutch plate so that was not the cause.

I concluded that the cause was weakening of the big diaphragm spring in the cover plate.

Has this been changed on your car?

just a thought.

ScaniaPBman.

Are you sure it was the correct clutch kit, and a good quality one?

Did you carefully compare the new & old parts before fitting?

Not a Transmech kit was it?

On 12/15/2024 at 9:30 AM, ScaniaPBman said:

I had a clutch failure as you described some years ago when on holiday.

it was changed by a local garage and I asked him to keep the parts for my inspection.

Much to my suprise there was adequate friction material on the old clutch plate so that was not the cause.

I concluded that the cause was weakening of the big diaphragm spring in the cover plate.

Has this been changed on your car?

just a thought.

ScaniaPBman.

Thanks for the steer .... yes the slave was shot to pieces and in fairness the clutch was within miles of end of life as well. So miserable job as it was it was worth it. I forget the make but was a decent one. Have to confess to normally going budget on all out workaday cars but as this one was being used by son and girlfriend to get to work, I bought decent .... slave and master were gen Ford and the clutch itself a decent make. I think the gear cables were Ford as well. In fairness it all went together nicely and gear oil changed as well. The brakes are also soft so hydralic does seem the most likely suspect. If weather holds up I'm going to check this this afternoon.

On 12/15/2024 at 1:34 PM, Alan G H said:

Are you sure it was the correct clutch kit, and a good quality one?

Did you carefully compare the new & old parts before fitting?

Fairly sure Alan yes. Even bought a new clutch alignment tool as our old one was in questionable condition. Reason to know that is that I did indeed order the wrong master and had to return it. Turns out the master was in near perfect order but we changed it all the same.

On 12/15/2024 at 1:37 PM, TomsFocus said:

Not a Transmech kit was it?

 

By pure good luck, I just found the order and it was a QH unit ... cover plate and CSC. I think QH are an OK make but although changed many clutches over the years, I'm far from expert, not in trade just maintaining our old machines. The Focus is only a few months old to us, not heavily used but clearly needing bits done. 

So far we did normal service stuff, also some rough idle so we did pipes and rubber bits that go soft behind engine. And then the slave unit failed horribly on that miserable magic roundabout in High Wycombe. One RAC, and Police and cones exercise and an 18 hour lorry relay back to Shropshire, we did the clutch exercise. Oh and the petrol filler neck leaking horribly but that can wait till it's warmer.

So far Ford Focus world has been a dream 🙂 .... in fairness there's always a shake down. Have the fun of these old units .... I think!?!

I'm not a fan of QH parts in all honesty.  I'd generally go LUK or Valeo for clutches.

Clutch slip can't be caused by air in the hydraulics.  That would cause the opposite problem and prevent you being able to disengage the clutch instead.

Slip can only be caused by contamination on the friction plate, or a weak spring on the pressure plate.

1 hour ago, TomsFocus said:

I'm not a fan of QH parts in all honesty.  I'd generally go LUK or Valeo for clutches.

Clutch slip can't be caused by air in the hydraulics.  That would cause the opposite problem and prevent you being able to disengage the clutch instead.

Slip can only be caused by contamination on the friction plate, or a weak spring on the pressure plate.

Ahh that's less good news. The bell housing and internals were degreased and the plate was brand new. I wonder if there's some other leak we didn't notice. Happy days! But appreciate the steer. I maybe jumped to that conclusion as one of the other users of the car said that brakes were also spongy and I think they are part of same system? 

Could be a leaky crankshaft rear oil seal which has contaminated the clutch plates ??

43 minutes ago, Phil3747 said:

Could be a leaky crankshaft rear oil seal which has contaminated the clutch plates ??

errr let's hope not but whilst the main engine unit hasn't been leaking there has been some drive leakage ..... we did see that steering rack leaking some. Trouble is a proper investigation of leaks not the easiest is these conditions.  Torches out in the morning.