Hard brake pedal

[mabbonizio]

Recently driving my friends 1985 230E (euro w123) the other day I noticed that the brake pedal is pretty firm in my 82 240D. Like to the point where I have to use a significant amount more pressure to bring the car to a stop than in my friends car.

My car had the following brake work done about a year ago.

- All new brake pads

- new front brake lines

- complete system fluid flush

The vacuum pump is healthy - I know this from going through the system to resolve my trans shifting issues.

Any thoughts?

[t walgamuth]

Could be a loose fitting in the vac hose to the brake booster?

[jake12tech]

Originally Posted by t walgamuth

Could be a loose fitting in the vac hose to the brake booster?

If there's no cracks in the vacuum hose and your pumo pump is putting out proper vacuum the booster is bad. I drove my 1992 300d around daily with a bad booster. It's annoying.

[Diesel911]

You did not give and numbers as to how much vacuum you are getting. You can get a free rental fuelpump/vacuum gauge at Autozone and likey other chain type autopart stores.

It is also possible for Brake Fluid to leak out of the rear of the master cyliner and from there into the power brake booster. I don't know if that would cause the symptoms you are hving.
Or it could be the power brake booster needs replacing. But taking the time to get a vacuum gauge is cheaper and less work.

When the check valve on my Vacuum Pump got gunked up I was gettling like 15 mmHg vacuum instead of the 22-24 mmHg I was supposed to get and I had hard braking.

[barry12345]

Brake friction materials can glaze up sometimes as well. Requiring substantially more force.

I have a couple of front calipers that I will pull and rebuild on our Honda civic. To hopefully restore more braking.

I think the pistons are far too tight. Was hard to get much piston movement the other day when having a quick look. Almost impossible. Front wheels are not getting hot. I just suspect the pistons are seized pretty tight in there. Or it has caused the brake material surface to heat glaze. You can break the glaze with sandpaper but best to wear a dusk mask when doing it.

I may have found a brake piston manufacturer in Canada here. That hopefully will sell me some new pistons when required. Have not contacted them yet. They are made in China as well but larger than I would desire minumin orders are required. Cheap enough It is not rocket science to recondition calipers. As long as you have a reasonable cost source of good new pistons when needed.

I have an ideal. After a quick contact with a brake caliper piston manufacturer. I think we just might be able to offer reseal kits and caliper pistons where needed at really good prices to members of this site. Nothing certain yet but no Chinese products. I will post pricing as soon as we get it together. Or if you would want Chinese reseal kits maybe as well. I doubt there will be much of a price spread and they do not have a good reputation anyways.

Many of our older Mercedes need a caliper reconditioning. Or if yours are still decent at least start changing your brake fluid out periodically. Since time is not a large factor when doing it yourself. You can get by with a length of clear soft vinyl hose available almost anywhere.

A pop bottle and just use gravity. Or spend a little to have a pressure system. Cost otherwise being just the new brake fluid. I was looking for something for an ex employee to do. Plus it gives me another interest. . Various other members are providing some services and you know we would not rip anyone off. Never was my thing anyways.

I had been looking at this area for a year or more as the price of rebuilt calipers has gone up substantially at least around here. Still cheaper in America but that will not last much longer I suspect. Other than junk level quality rebuilds. Those are done by companies that do not throw out the core calipers that should not be rebuilt. Just rebuild them all instead. Also it is only reasonable to expect the inferior quality Chinese reseal kits to be used in them.