Lotus Elan

Getting the Clutch to bleed

PostPost by: Matt Elan » Sat Dec 02, 2023 5:36 pm

Well after my pedal box saga elsewhere on the forum, I could not get my clutch to bleed. So I investigated further and found that various people on here had made extended 'clutch slave cylinder bleeder hoses'. These are a hydraulic brake type pipe with a small (3/8) banjo on one end and a 'bulkhead bleed fitting on the other. The banjo end replaces the bleed nipple on the slave cylinder, the pipe is fed up to the bulkhead and by making a little bracket it can be fixed to the bulkhead. Then the clutch can be bled in comfort.
Here is the actual fitting as supplied along with the slave cylinder:
IMG_1229.jpg and

and here is the bleed nipple attached to the bulkhead:
IMG_1238.jpg and


I ordered two from Exact Engineering (Hose and Fittings) Ltd of Totnes, Devon, UK (Tel 01803 866464, sales at exact-eng.co.uk), and they arrived the next day for the princely sum of £51.35 - so around half that for one.
Parts used to construct the pipes were:
B2043-03S Bulkhead bleed fitting, 3/8 unf (male)
924-03s Lock Nut 3/8 unf
300-03 Stainless steel braided teflon hose - 16 inches
3920-03S Banjo Striaght/Extended 10mm-3/8
Banjo bolt Single 3/8 unf 18 mm long
Copper washers solid 10.20 x 15.20 x 1.0mm

The assembly bolted on easily and, after I had replaced the clutch master cylinder, allowed the system to be bled one handed and very quickly. Any air in the system should (and did) end up going up the pipe making bleeding a lot easier than before and with no need to jack the car up. The only issue was the pipe was little short - I should have made it clear I wanted the pipe without fittings to be 16 inches which gives plenty of fiddle factor when positioning the pipe on the bulkhead. Luckily my shorter one still works ok but I need to move the washer bottle off its bracket to get at it.
Matthew Vale - Classic Motoring Author
1968 Plus 2 - Somewhat cosmetically and mechanically modified
1969 Plus 2S - Currently undergoing nut and bolt restoration
Visit me on matthewvale.com
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PostPost by: alan.barker » Mon Dec 04, 2023 9:53 pm

Hi Matt,
Imho to fit that will change nothing to bleed air out. It's just easier access to outlet on Slave.
The problem is the bleed outlet on the Slave Cylinder is not at the very top of Slave. The Slave needs to be rotated so outlet is at 12o'clock. To do that the flats on the Slave that stop rotation to 12o'clock need to be modded. Or Slave bled before fitting into Bellhousing hole and fitting of Circlip.
Alan
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PostPost by: Matt Elan » Tue Dec 05, 2023 7:26 pm

Hi Alan
I appreciate your comment and while I agree with you in principle, the solution seems to have worked for me. I suspect that as you can really get a good volume of fluid through the system easily, and can bleed it several times without having to be grovelling under the car the air in the system is eventually expelled. Any air in the system will eventually end up at the highest point i.e. at the nipple; but it will take a few attempts to get rid of it all. Also it removes the possibility of air being introduced into the slave cylinder from around the original bleed nipples threads; in any case it seems to have worked for me.
Matt
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1968 Plus 2 - Somewhat cosmetically and mechanically modified
1969 Plus 2S - Currently undergoing nut and bolt restoration
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PostPost by: alan.barker » Wed Dec 06, 2023 4:52 am

Hi Matt,
I'm pleased it works and it does look neat.
Alan
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PostPost by: RichardS » Wed Dec 06, 2023 4:26 pm

Thanks for posting Matt, useful to have all the part numbers.
Have put off changing my clutch fluid due to the awkwardness!
One of our American colleagues posted a similar set up a few years ago and good to have the UK version
Will add to my list of possible future mods
Richard
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PostPost by: RichardS » Wed Dec 06, 2023 4:27 pm

Is the target for 4th gear 500 posts?!
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PostPost by: smo17003 » Wed Dec 06, 2023 7:20 pm

An alternative UK supplier for a clutch bleed extension hose is Car Builder Solutions. I listed the parts that I used in this previous topic viewtopic.php?f=37&t=53000&p=386184#p386184

Fitting one certainly helped with the clutch actuation on my S4.

Mike
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PostPost by: patrics » Sat Dec 16, 2023 5:10 pm

Hi,
The easiest and cheapest way to bleed the clutch is the following:
Without the slave fitted bleed the hose – I use a 10mm barrel nut fitted with a bleed screw – I’m assuming you have a banjo fitting to the slave.
Without the slave fitted fill it with fluid.
Again without the slave fitted connect the hose – make sure the hose timing is right. Also when connecting keep it level or slightly above the master cylinder.
Now again keep it level with the master cylinder completely remove the bleed screw.
If you now move the slave up and down a bit you will see the level rise and fall inside the bleed screw hole. Depending how well you originally filled the slave, make sure the reservoir remains topped up, play with the level in the slave (gently moving up and down about the height of the reservoir) so that it is completely full and then refit the bleed screw.
Fit the slave to bell housing and check the bleed screw torque.
When bleeding you need to make sure the piston is fully retracted within the slave.
After adjustment check the fluid level.
You will not loose any fluid as long as you keep the slave at same height as the reservoir

Regards
Steve
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PostPost by: ElanDNA » Sun Dec 17, 2023 11:19 am

A few years ago, when I replaced the clutch slave cylinder, I was also faced with the bleeding problem.
I made it easy for myself and everything was done quickly and cleanly.
First I wrapped some Teflon tape on the thread of the bleed screw to make it tight. Then I fitted it to the BOTTOM of the slave cylinder and loosened it about a quarter of a turn. Fitted the pipe at the TOP. Everything was now completely empty.
I now connected the fluid reservoir under the car to the bleed screw with a hose. I now sucked the fluid up through the small ventilation hole in the cover of the clutch cylinder reservoir, using a suitable device. It takes a little time, but is convenient. When there was enough fluid in the clutch cylinder reservoir, I pressed the clutch lightly by hand two or three times to really remove all the air from the slave cylinder. Then I just had to tighten the bleed screw, adjust/fill everything correctly and it was done.
Urs
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