UNUSUAL CLUTCH FAILURE ON 4200 GT ............. SOLID BRAKE FLUID!

Geo

Member
Messages
616
I purchased a manual 4200 GT in December last year thinking that at 25000 mile I should have little or no problem from the clutch. Well, after about 200 miles the changing gear became a bit balky and at 250 miles the clutch wouldn't release properly with the pedal going about halfway down before feeling resistance.

At first I thought I had a hydraulic leak, but could see no evidence of this anywhere, also the fluid level was sitting on the upper mark of the joint Clutch/brake reservoir. I then suspected that air had somehow entered the system so decided to bleed it.

Let he fun begin!

I jacked up the car on axle stands and crawled underneath to access the clutch bleed nipple. This was extremely tight and had to be freed off using a ratchet and socket before using a spanner for the bleeding operation.

To make things nice and easy (laughs like ****), I purchased a pressure bleeder. This is an excellent piece of kit that holds up to 2.5ltr fluid and pressurises the system at about 20PSI. Once fitted to the reservoir and pressurised, the clutch pedal jammed rearwards I crawled under the car and released the bleed nipple. Did the fluid flow out in a flowing stream, did it ****. With the bleed nipple open, there was only the slightest drip of fluid from the end of the plastic hose.

After lot of head scratching, I eventually discovered that the brake fluid on the line down to the master cylinder had solidified having the appearance of solid calcium or icing sugar. Although the brake fluid in the reservoir was fresh and had obviously been changed as required in servicing, the fluid in the clutch line had never been changed since it left the factory fifteen years ago! I suspect there will be quite a few cars that have a similar shared clutch and brake reservoir system suffering from ancient fluid in the clutch line.

IMG_5031.JPG

I removed the master cylinder and opened it up only to find a build up of this hard white deposit inside. The hose that feeds the master cylinder was like a rod of iron, and when flexed cracked and crunched. I blew it through with a high pressure air line and a large quantity of white pellets shot out. After a bit of experimentation I discovered that boiling water dissolves this deposit very easily.

IMG_5037.JPG

Not happy with price that Maserati charge for a new master cylinder, I purchased one for an Audi TT/A3 ( Sachs Clutch Master Cylinder 6284000032 or 6284000033) which is exactly the same dimensions inside and out. The only difference is the length of the actuating rod is about 25mm too long on the Audi version.

IMG_5035.JPG

I dismantled the new cylinder and replaced the piston and rod assembly with the original from my car. It is a bit if a fiddle as it I'd not meant to be taken apart. It involves compressing four plastic barbs while gently pulling on the rod to allow the cap to come out. As the cylinder was getting binned, to save time I just cut the cylinder with a hacksaw to free the rod.

IMG_5039.JPG

IMG_5041.JPG


The most awkward part of the job was locating the ends of the circlip that holds the rod into the clutch pedal. You are working upside down lying on your back and unable to see how the clip lies. I used a piece of plasticine and pressed it into the back of the pedal where the rod goes. When carefully removed, you will have an impression showing the orientation of the circlip ends, and you will also see what size of circlip pliers you need for best fit.

Once fitted the new cylinder was easy to bleed using the pressure bleeder, but do ensure that the pedal is jammed fully to the rear first. If the rod is more than 1mm into the cylinder, it won't bleed.

Cost of cylinder £26.26 and Pressure Bleeder £45.91 both prices included carriage.

The car has covered about 1700 miles since replacing the cylinder and everything is operating perfectly.


MANY THANKS TO EDWIN247 for help in sourcing master cylinder from his post here: https://www.maseratilife.com/forums/coupe-spyder-gs/86257-4200-gt-clutch-master.html
 
Last edited:

TimR

Member
Messages
2,656
I suspect there will be quite a few cars that have a similar shared clutch and brake reservoir system suffering from ancient fluid in the clutch line.
I really hope not ! I struggle to see how a fluid change at service would fail to prevent and detect the problem both.
I felt a bit sick when you said you bought a 10K car with 25K miles on it....! :)
 
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Geo

Member
Messages
616
I really hope not ! I struggle to see how a fluid change at service would fail to prevent and detect the problem both.

If whoever does the fluid change either fails to realise that the clutch is fed from a joint reservoir, or is too lazy to to find the clutch bleed nipple and drain the fluid from the clutch, you will probably have clutch issues later at some time.
 

conaero

Forum Owner
Messages
34,593
One thing to add to bleeding the clutch on the 4200 manual, Terry had to do his in France and couldn't get it to firm up. When he got it home he worked out that you have to pull the clutch pedal up as far as it goes to allow fluid in. If its floppy then no matter how much you pump it, you will only pump out the fluid thats in it and not draw in fresh fluid.
 

Geo

Member
Messages
616
One thing to add to bleeding the clutch on the 4200 manual, Terry had to do his in France and couldn't get it to firm up. When he got it home he worked out that you have to pull the clutch pedal up as far as it goes to allow fluid in. If its floppy then no matter how much you pump it, you will only pump out the fluid thats in it and not draw in fresh fluid.

Very important indeed Matt, thats why I said to jam the pedal to the rear before you start. It only takes about 1mm movement of the piston to close off the port that allows bleeding. I measured this by blowing through the new cylinder then moving the piston.
 

2b1ask1

Special case
Messages
20,220
I just wonder if it has has some DOT5.0 in it at some point to create those crystals? Never seen anything like it myself, have had to deal with some ancient fluid in the past.
 

Zep

Moderator
Messages
9,110
I just wonder if it has has some DOT5.0 in it at some point to create those crystals? Never seen anything like it myself, have had to deal with some ancient fluid in the past.

I have heard of it before, I was advised to flush my brake fluid every 2 years by pushing 5 litres through it to prevent solidification. I thought mixing mineral and synthetic produced sludge, but not crystals?
 

Geo

Member
Messages
616
I just wonder if it has has some DOT5.0 in it at some point to create those crystals? Never seen anything like it myself, have had to deal with some ancient fluid in the past.

Like you I've dealt with old brake fluids and never seen complete solidification. I have come across jelly, maybe that is the stage before it goes solid. If there are any analytical chemists on the forum, or any one knows one, I still have the solid samples. As I said in my original post it melts away like sugar when hot water is poured on it.
 

Scaf

Member
Messages
6,512
Google...........

https://www.cyclepedia.com/manuals/online/free/brakes/hydraulic-brake-fluid/

Glycol brake fluid is hygroscopic, that is it absorbs moisture from the atmosphere. The moisture will lower the boiling point of the brake fluid over time. The brake fluid should be replaced every two years to combat this problem. Always use fresh brake fluid from a newly opened container to avoid using brake fluid that has already begun absorbing moisture. If the brake fluid is not changed it will continue to absorb moisture, and eventually it will crystallize and form deposits inside the brake system that can cause the seals to fail and components to seize.
 

allandwf

Member
Messages
10,958
I realised it was hygroscopic, but never realised it would crystallise to that extent. If crystallised like that then is the fluid more water than not? Learning all the time as they say.
 

masertel

Member
Messages
102
One thing to add to bleeding the clutch on the 4200 manual, Terry had to do his in France and couldn't get it to firm up. When he got it home he worked out that you have to pull the clutch pedal up as far as it goes to allow fluid in. If its floppy then no matter how much you pump it, you will only pump out the fluid thats in it and not draw in fresh fluid.

Well spotted Matt.

I can confirm I had the same problem on our trip to Le Mans. The clutch pedal went right to the floor and would not pump up to a solid pedal. Unfortunately as in France I couldn't work on the car and had to have it collected and taken to a garage for repair (thankfully the AA sorted out the logistics and did a great job in this respect).

Unfortunately the French mechanics couldn't get the fluid to bleed through and even resorted to removing the feed hose from the reservoir and forced compressed air down the feed pipe. After 1 1/2 hours they gave up and the car stayed on the ramp over the weekend while I attend the race. The only plus point was as not driving I could drink more lol.

Long story short- the garage wanted to ship the car back home at the expense of the AA which would take up to 6 weeks. Not having any of that I jumped in the car and started it in 1st gear and made my way home without the use of the clutch. Once moving massaging the gear change from 1st to 6th took a little time to master but at least I got home.

As Matt pointed out, once home I tried to bleed the clutch using a vacuum bleeder but had the same problem as the french mechanics. On further investigation I noticed the clutch pedal was not returning back fully by only 1 or 2mm. Hey presto after manually pulling the clutch pedal back the system started to bleed fluid as it should and the clutch pedal firmed up- job done. Have since purchased a new clutch return spring from Euro spares for £9.50 as it would appear the spring weakens over time and doesn't pull the clutch pedal back fully.

As I change the brake fluid every 2 years thankfully had no issues with the fluid crystallising. Its very easy to overlook bleeding the clutch which is a shame as it's not difficult to do on a ramp but I suspect most are not changed during a service. The only time a garage is likely to bleed the clutch is when a new clutch is fitted and as the clutch can last well up to 80000 miles the fluid may not have been change in some cars for 15 years hence the problem of crystallisation rearing it's ugly head.

Hope this feedback helps and all gets sorted.

Terry