Independent Renault Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
2008 grand scenic 2.0 L DCI 150. I've been trying to have a vacuum servo leak sealed
for months now and seem to have found a load of totally incompetent so called mechanics.
They have so far replaced the servo unit, the connecting pipe between vacuum pump and servo, a
seal on the pump to no avail. Even suggested front discs and pads and a new ABS unit!!. Has anybody got any
suggestions?
 

·
Premium Member
Joined
·
3,314 Posts
How do you know that you have a vacuum leak .................. and in the servo of all places?

Easy enough to isolate if its in fact true - pull pipe from servo side and block it there and your vacuum pump should be able to supply all the vacuum required for eg turbo or whatever is driven off it - if it doesn't then you have a pump or pipe leak - if vacuum restored need to replace servo (!)

They cannot sort this simple issue?o_O
 

·
Sexy at 71 super mod..
Joined
·
24,752 Posts
How do you know that you have a vacuum leak .................. and in the servo of all places?

Easy enough to isolate if its in fact true - pull pipe from servo side and block it there and your vacuum pump should be able to supply all the vacuum required for eg turbo or whatever is driven off it - if it doesn't then you have a pump or pipe leak - if vacuum restored need to replace servo (!)

They cannot sort this simple issue?o_O
Was going to suggest he changed his garage but it may have sounded pedantic ?
 

·
Registered
Joined
·
2 Posts
Discussion Starter #4
2008 grand scenic 2.0 L DCI 150. I've been trying to have a vacuum servo leak sealed
for months now and seem to have found a load of totally incompetent so called mechanics.
They have so far replaced the servo unit, the connecting pipe between vacuum pump and servo, a
seal on the pump to no avail. Even suggested front discs and pads and a new ABS unit!!. Has anybody got any
suggestions?
I'll say to start that this is in Spain. Classic test as I know it: clear vacuum by pumping pedal, which Has already cleared itself; start engine and pedal slowly depresses but with considersble foot pressure required; turn off engine and pedal immediately pushes back with considerable force. Problem first occurred when descending a mountain road and servo assistance failure- very scary!
 

·
Premium Member
Joined
·
3,314 Posts
OK this may turn into a head-scratcher for you but imo you actually dont have a "booster vacuum leak" or any vacuum "leak" problem as per your thread title at all but you have a "too much vacuum" problem and this is why the garage cannot sort a non-existent "leak" problem.

Internet is full of the diesel brake pedal creep behavior of diesels in all brands as a result of diesel pump action into a sealed system where a huge sensitive booster is fitted ................. https://www.google.com/search?client=firefox-b-d&channel=crow&q=diesel+vacuum+pedal+creep.

There are many threads here on this forum on the subject too but I will be damned if I can figure a sensible way to make the search function work with me rather than against me so I cannot link to any yet - I know I have seen them in the past too. Perhaps there is a clever guys reading this with better search skills that will post examples.

IMO if you can say your brake system has no fluid leaks, and the pedal with engine switched of can get rock solid with minimum travel and can stay there for many minutes, is behaving totally normal.
 
1 - 5 of 5 Posts
Top