Mercedes R129 - Brake fluid change question

Mercedes R129 - Brake fluid change question

Author
Discussion

pcn1

Original Poster:

1,078 posts

189 months

Thursday 19th August
quotequote all
My old 1998 SL is due a brake fluid change. Sort of job I've done on a couple of other cars and bikes over the years.

But I'll confess as not being fully conversant with the fact you need to pay special attention for ABS systems to fully bleed through.

So, would I need to take this car to a garage with Mercedes Benz (Star ?) software that actuates the ABS to bleed it correctly, there is no way a home spanner man can do this with basic tools ?

I don't want to buy expensive diagnostic tools for a one off job. I think *correct me if I'm wrong* its only around £60 ish for a garage to do this anyway which may be the simple solution ?

Thanks

E-bmw

6,394 posts

122 months

Thursday 19th August
quotequote all
You can bleed it in the normal way as long as you keep the reservoir topped up.

If it falls & lets air in you will need to take it somewhere.

Stegel

1,728 posts

144 months

Thursday 19th August
quotequote all
+1. My 97 SL laughed at a pressure bleeder, refused to cooperate with a MightyVac vacuum bleeder so I switched to the conventional method, with a daughter pressing the pedal, and no issues at all. As said, keep the reservoir topped up. (I don’t think Star has a role to play with brake bleeding in R129s).

Ray Luxury-Yacht

8,847 posts

186 months

Thursday 19th August
quotequote all
I did my 1990 R129 myself several times over my ownership, using the conventional method - assistant to gently pump the pedal, whilst I ran round the bleed nipples. Using DOT 4 fluid, although you can use DOT 5.1 (NOT DOT 5.0).

Start at the bleed nipple furthest away from the master cylinder / reservoir, and work towards it.

Never had a problem, brakes worked perfectly, no air in the system.

23.7

22,555 posts

153 months

Friday 20th August
quotequote all
I did mine using a Gunson pressure bleeder, it's a pre ESP model though.

pcn1

Original Poster:

1,078 posts

189 months

Wednesday 25th August
quotequote all
Thanks for the reply's, I'm confident to do this the old fashion way.

But like I say, from reading and watching YouTube I gather you wont "fully" bleed all the old fluid out of a ABS system unless the ABS valve system is operated in a certain order. I'm just guessing there's very little fluid in this "system" and maybe in the scheme of things it just doesn't really matter.

But I'm open to advice from those more informed.

Thanks

E-bmw

6,394 posts

122 months

Wednesday 25th August
quotequote all
The volume is miniscule, but if you REALLY want to make sure the fluid is cycled the generic way is after bleeding activate the ABS a few times by braking hard on a loose surface in a safe area.

Chris32345

1,709 posts

32 months

Wednesday 25th August
quotequote all
As other have said as long as you don't let the fluid level drop too low and let air into the system it's not worth worrying about
The fluid in the abs valves is tiny and we'll sealed anyway so won't be exposed to half as much air as the rest of the system

pcn1

Original Poster:

1,078 posts

189 months

Thursday 26th August
quotequote all
Thanks for the reply's.

Now just need to find the time to do the job ! biggrin