Hello guys!

I'm the owner of Volvo V40 1998 (1.9TD 66kW) with Renault engine B4194T. Unfortunately I had many problems with this car. Currently I have a problem with hard brakes. I need to push really hard on it in order to start braking. I've noticed that I have a good brake for a first time (after acceleration) and the second time it feels really hard to push. So I need to give some gas to the car i order to have a 'good' brake. I've already changed Brake Booster (Bosch 30857437) because I heard some squishing noise under the brake pedal when pressure applied - after this squishing sound disappeared. I've also changed Vacuum pump (OE-8200399371) and the problem with hard brake is still there.

I'm still thinking that there is something wrong with vacuum pump... I changed two of them already and the brake feels the same. I don't have original rubber seal which is going between engine head and vacuum pump. Can that be a problem? I used some red (flat) seal which has the same shape as pump, because I don't have original one which is going in the pump canal. My friend told me that vacuum pump can be less effective when there is oil leak? Is oil coming from the engine head to vacuum pump? -Is that important and can it cause problems l have? How much oil is needed for vacuum pump to work properly?

I would really appreciate if you guys can give me some answers here. If you have any thought about possible possible problem in my case, please reply.

Thanks.