Register Login
Mr FIAT - Your #1 source for vintage car parts
Guide Tools Search this Guide
<!-- google_ad_section_start -->Clutch Slave Cylinder swap, air bleeding, plus modification. [1,4 8V]<!-- google_ad_section_end -->
Clutch Slave Cylinder swap, air bleeding, plus modification. [1,4 8V]
How to replace and bleed the leaky hydraulic clutch actuator.
Published by GrandePunto PL
Difficulty Level: 1

User Rated:Unrated

Show Printable Version  Email this Page 
Wink Clutch Slave cylinder modification to stop leaks.

This is clearly bad design. Master has a joint to allow rod cocking. Slave has none, so those "2 degrees allowance" may be too much (and it is in my car - or, maybe there is something else wrong, I don't know).
But. In power hydraulics world this is unacceptable at all, to tilt the piston and seals!
Click image for larger version

Name:	25_FTE_style_slave.jpg
Views:	9
Size:	116.0 KB
ID:	217385

How can it seal when you cock it? Who designed this?
Click image for larger version

Name:	26_Piston_Seal.jpg
Views:	10
Size:	138.8 KB
ID:	217386

By the way, the boot should have a vent, check this when you buy a new cylinder...
Click image for larger version

Name:	27_Boot_-_No_air_vent.jpg
Views:	8
Size:	112.6 KB
ID:	217387

Now. Modifications. Idea 1 - not tested. Just add an o-ring (brake fluid compatible).
Click image for larger version

Name:	28_Idea1_O-ring.jpg
Views:	6
Size:	157.5 KB
ID:	217388

Idea 2 - not tested. Stack the original seals (if you have 2 slaves).
Click image for larger version

Name:	29_Idea2_Seals_Stack.jpg
Views:	6
Size:	153.7 KB
ID:	217389

Idea 3 - not tested. Extra piston. Diameter is the same as brake cylinders = 20,6 (or 20,64 mm). But they take too much stroke. And metal can be too hard on the plastic body, bore.
Click image for larger version

Name:	30_Idea3_BrakeCylinder_Piston.jpg
Views:	8
Size:	156.4 KB
ID:	217390

Idea 4 - done, testing (for almost a year now), works great. Custom made piston, plastic (PA - polyamide), plus seal from brake system (drum brake cylinders, from Punto 1). Of course, it takes a stroke space, but there is still plenty of it available for future wear compensation (but it must be checked periodically).
Click image for larger version

Name:	31_Idea4_Custom_Piston.jpg
Views:	15
Size:	214.1 KB
ID:	217391

Diameters are maximum. If anyone will ever make this mod, do it a bit smaller (all diameters smaller by 0,05-0,10 mm). It works great, but feels a bit on the tight side. Important thing is, it should push on the center of the original push rod, not crushing the seal.
Click image for larger version

Name:	32_Slave_Extra_Piston_Drawing.jpg
Views:	27
Size:	128.3 KB
ID:	217392
Animated GIF (click).
Click image for larger version

Name:	33_ExtraPiston_GIF.gif
Views:	11
Size:	479.0 KB
ID:	217393

There is a grease compatible with brake fluids. Use this during assembly.
Click image for larger version

Name:	34_ATE_BremsZylinderPaste.jpg
Views:	4
Size:	21.9 KB
ID:	217394
Thanks Davren thanked for this post
FIAT Forum Useful Links:
Donate to FF | Buy FF Merchandise | Classifieds | FF Insurance | How-to Guides

<<  <    (Page 3 of 3)    > >>
Currently Active Users Viewing This Guide: 1 (0 members and 1 guests)
Guide Tools Search this Guide
Search this Guide:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump
Similar Threads
Guide Guide Starter Category Comments Last Post
(G) Clutch slave cylinder bleeding Gizzybusy Fiorino (Mk3) 22 12-12-2020 08:48
(G) bleeding new clutch slave cylinder Brian1 Multipla 3 29-10-2014 10:10
(T) 1.4 Tjet Clutch with Slave Cylinder or Concentric Slave Cylinder? Eridanny Bravo 9 22-12-2013 22:25
Clutch Slave Cylinder, bleeding? joem FIAT Boo Archives 1 09-09-2003 15:55