Rabs

Hi any recommendation on pressurised brake bleeders for c4. I see on a lot of threads people recommend motive bleeder but they are not available in the uk. Thanks in advance.

pi5tolpete

Build your own! I did. Lawn sprayer, pressure gauge to 30 psi, and a Doorman reservoir cap. I also bought a swivel to allow for threading the cap on and off without twisting up the hose. Total cost of about $40.

onceover

I've got this one: http://www.ebay.co.uk/itm/Motive-Pro...0abb3#shpCntId

Been awesome so far. Looks like they ship to the UK

Pesty

I used vacuum last time are pressure ones better?

tbennett017

For the C4, pressure is necessary. You can't accomplish a bleed without it.

ToreB

I bought a Motive bleeder directly from their US website, it was delivered to Norway in 5-6 days. Bleeding is a breeze with it using the procedure description in the 993 Bentley manual.
Cheers,
Tore

Pesty

Oh.

I replaced the hard lines and callipers drew all the air out until fresh fluid came through.did I miss something?

Harry Apps

Simples! I use Gunson Eezibleed for my cars. It's inexpensive, does the job perfectly. Uses pressure from one of your wheels (or someone else's!).

onceover

Theres a lot more than just the brake calipers that need to be bled on the C4's. DIY here: https://rennlist.com/forums/964-foru...procedure.html

tbennett017

^^^^^ Yes. ^^^^^^^^ You might want to find Adrian Streather's 964 Companion book and read up on what's in the Frunk... take a look near the battery and you'll find a lot of equipment that isn't 'normal'... as the C4 uses a high-pressure hydraulic system for both the brakes and the diff locks. This back in 1989 was the bees knees, but it's expensive and complex. Simply doing a standard vacuum bleed doesn't really do the trick.

Harry Apps

Why not? All a pressure or vacuum bleed does is to shift the fluid through the system and removes the need for pedal pumping (except diff locks of course). What are we missing?

alexjc4

You can bleed the 964 brakes fine with vacuum, I have done on my car many times.

I also have a gunson pressure bleeder (readily available in the UK) which I've used when I wanted a bit more oof eg if the system was fully dry.

I however recently changed my views a little and on very old systems I think pressure bleed is safer on old potentially worn out seals than vacuum - I recently had an old ABS unit (not in the 964) spring a leak after vacuum bleeding and I think it's because the old seals could hold the pressure (which they see all the time of course) but not the vacuum.

The 4wd stuff in the frunk can be bled without any special tools (no vacuum or pressure equipment since it supplies it's own pressure) you just need to fully the procedure in Adrian's book. The 4wd locks can be done with or without the bosch "hammer". I have only done them "without", you just have to pressurize the locks but using the **** in the centre console and then crack the bleed nipple, and repeat many times.

Mixter

+1 ^^^ exactly the way I've done mine. I use pressure from my air tool compressor with some tubing and a modified rubber maid cap that happens to fit perfectly on the brake fluid reservoir and also use the **** in the center console method for the diff locks. No need for any special bleeder or diagnostic tools.

Goughary

The thing to watch out for on the C4 if not using a wet pressure bleeder like the motive, is that when you bleed things like the bomb in the frunk, you can empty the reservoir quickly and introduce air to the system if you aren't watching. Outside that, bleeding the system, while easier w the right tools, can be done as described above with zero issue.

alexjc4

Oh yes well worth pointing this out - the bomb dumps like 500ml in one squirt so you drain the reservoir fast and fill up you waste container (I've moved up to a 5L waste container), you can also make a really impressive fountain of brake fluid if you aren't careful