300 tdi brake servo and vaccum pump testing
Posted 13 January 2008 - 01:03 PM
1. There is no test given for the vacuum pump. How much "sucking" does it do? If I remove a pipe and stick my thumb over the pump connector, should the amount of suction be noticeable? i.e. will my thumb stick to it?
2. Is the test on the servo (which involves purging the vacuum, keeping the pedal pressed while the engine is started etc) only going to show up a fault in the servo, or could something else cause the same symptoms i.e. if the vacuum pump is not working correctly?
3. Are there any checks I should do before checking the servo to eliminate them first?
By the way, it does not have ABS.
Posted 13 January 2008 - 01:46 PM
Any ideas on why I'm getting the excessive pedal travel initially? For what it's worth, the rear pads were replaced about 1-2 months ago with Mintex, and the front ones appear to have quite a bit of material left when I checked them yesterday while bleeding the brakes.
Am I going to be spending some money on a new master cylinder?
Posted 13 January 2008 - 01:57 PM
That said, if the vac pump was not working, you would probably have to press the pedal very hard to stop the beast if it was not giving a decent vacuum. These pumps tend to be pretty reliable.
Disco 300tdi - You only need 6 tools and 5 of them are hammers
Honda FRV - don't know how many tools 'cos I haven't had to fix it (yet)
Posted 13 January 2008 - 01:58 PM
Posted 13 January 2008 - 04:22 PM
Posted 13 January 2008 - 08:14 PM
Change the master cylinder - even if it is not the fault, it's probably not 100% if original.
Free waste vegetable oil collection in Somerset
He seems to have a veg oil fetish.
Posted 13 January 2008 - 08:54 PM
Posted 13 January 2008 - 09:22 PM
Edited to add: Just to be clear about the symptoms, I do get brakes on the first pump, but it's firmer (ooer ) on the second pump. Is the consensus still the master cylinder?
Posted 13 January 2008 - 10:11 PM
It is very rare for the bore of a cast iron cylinder to be scored nowadays. The piston assembly is usually alloy, so is usually what suffers if there's any metal damage. Seal failure is generally the only problem in my experience.
Posted 14 January 2008 - 10:49 AM
When I was bleeding the brakes, I noted that the reservoir was split into two sections (front and rear (nearest the servo)). As I bled the brakes, only the rear compartment was draining of fluid. Does this point to anything else? Could it just be a blockage between the reservoir and the cylinder body which means the secondary piston is not getting any fluid?
Posted 14 January 2008 - 11:30 AM
The chamber is split into two compartments so that if you have total fluid loss at (say) the rear, the front brakes will still work as they have what is in effect their own seperate reservoirs.
Ryan (still trying to get out of actually doing something this morning).
Posted 14 January 2008 - 01:34 PM
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