More hydroboost issues...

[-83MONTESS-]

I just mounted the hydroboost to the firewall, switched out the brake pedal for the one that came with the hydroboost and mounted my master cylinder. Everything went together smoothly with no hang ups. I hit the brake for the first time and the pedal went down to the floor easy(I havent bled them yet obviously) but it stayed there. No matter what I did the pedal would not come back. So I took the master cylinder back off to get a better look. It took about 15 minutes to get the master cylinder off because the hydroboost plunger was stuck in the back of the master cylinder which explains why my pedal didnt come back. Am I missing a piece between the two???? I bought the hydroboost as a complete kit but didnt find anything that goes between the master and pump. Thanks

 

[-83MONTESS-]

Update: I pulled the old master that came with the hydroboost out of the scrap pile and mounted it. Now the pedal feels good as in it returns like it should. I dont understand why or how because the new master looks exactly the same.

 

[deanlemans81]

could just be a defect in the new master cylinder. I used to have a thread from a buick site with all the partnumbers and such for a hydroboost swap, let me see if I can find it for you.

 

[deanlemans81]

could just be a defect in the new master cylinder. I used to have a thread from a buick site with all the partnumbers and such for a hydroboost swap, let me see if I can find it for you.
got it, see if this helps
http://www.turbobuick.com/forums/forums/how-tos.157/

 

[-83MONTESS-]

Well turns out it was something stupid that should have never made it out of the factory. The retaining ring for the primary piston was a snap ring with big ends on the new master cylinder. The old one was just a ring with no ends. The bigger ends on the new one got stuck on the hydroboost when I pressed the pedal which is why the pedal wouldnt return. I ground down the ends of the snap ring and it works fine now. I just cant get the air out of it Cant win for losing but here's some pics

The old master cylinder
hydroboost retaining ring 1 by bwollens1983, on Flickr

The new one. Notice the ends of the snap ring
hydroboost retaining ring 2 by bwollens1983, on Flickr

 

[pontiacgp]

I have that snap ring with the holes on my master and the rod that pushes on the piston sits in the center cavity. It works fine with that snap ring. Maybe the hydroboost is different, what does it have to push on the piston in the master.

 

[-83MONTESS-]

I have that snap ring with the holes on my master and the rod that pushes on the piston sits in the center cavity. It works fine with that snap ring. Maybe the hydroboost is different, what does it have to push on the piston in the master.

The pushrod on mine sits in the little hole on the master but when the pedal is depressed the part holding the pushrod extends out. I will post a pic shortly. The ring left 2 pretty good sized scratches on it. Which explains why I had to pry the master off with 2 huge flatheads.