Front brakes not locking up

[nailpounder]

did you fallow the welwood brake pad bedding  procedure  you might try to re bed the pads  get them hotter

 

[tony-muscle]

did you fallow the welwood brake pad bedding  procedure  you might try to re bed the pads  get them hotter

I did follow this procedure as close as possible. Do you think from the picture that they are glazed? I am trying to figure out how does a glazed pad look compared to non-glazed? It is definitely shinny, but I don't know if that's enough.

 

[73pony]

Do you think these pads are glazed or do they look normal? I used the flash and the surface looks a bit shinny. Any thoughts?

Those appear to have some glazing but not severe. It might also be from the flash in the pic hard to tell

 

[tony-muscle]

Do you think these pads are glazed or do they look normal? I used the flash and the surface looks a bit shinny. Any thoughts?

Those appear to have some glazing but not severe. It might also be from the flash in the pic hard to tell

Here is a picture without flash.

 

[73pony]

They don’t look badly glazed at all.

 

[nailpounder]

do the rotors have good cross hatching ?

 

[Bentworker]

That really does not make any sense that you cannot lock up your front brakes.

You have any pictures of the combo valve from when you rebuilt it without the internal proportioning?

Rear port on the master goes to the combo valve which is basically acting as a glorified tee to the two front caliper lines?

Front port on the master is going to the combo valve that is no longer a combo valve - then to an adjustable prop valve then the rear brakes?

Why did you choose to retain the combo valve?

 

[B229218]

Some time ago I replaced the brakes at the four corners. In the front I installed Wilwood's 11.3" rotor kit with 4-piston calipers (140-13477). In the rear I installed a conversion kit that uses the ElDorado type of rear brake calipers. Recently, I replaced the master with a Wilwood tandem (260-8555) with a 1" bore. All the tubing and hoses are new. I also have a proportioning valve on the rear circuit. That said, everything has been replaced except the combination valve. However, I rebuilt the combination valve with the kit from Muscle Car Research and removed the integrated proportioning valve springs of the combination valve. My issue is that the car is not braking as I was hoping it would. With the proportioning valve all closed I am able to lock the rear brakes, but I have not been able to lock the front brakes. I expected that with the brake system that I have I should have been able to lock up the front brakes. I understand that I don't actually want to lock the front brakes for efficient braking, but the fact that I am not able to lock them when fully stepping on the pedal is telling me that something is not right. The only suspect I have now is the combination valve and I am wondering if I should eliminate it and go with a tee to the front. What else can be in the combination valve that could cause the front brakes to be inefficient or am I missing something? I guess that the only thing I will lose is the functionality of the idiot brake light.

You might want to try a power brake bleeder, like this. There website has a adaptor that seals to top master cyl. just pump up to 20 pounds and ALL bubbles are expelled, thats how o.e.m. are done today, works like a charm, regardless of loops in line, ect. 

 

[tony-muscle]

That really does not make any sense that you cannot lock up your front brakes.  

You have any pictures of the combo valve from when you rebuilt it without the internal proportioning?

Rear port on the master goes to the combo valve which is basically acting as a glorified tee to the two front caliper lines?

Front port on the master is going to the combo valve that is no longer a combo valve - then to an adjustable prop valve then the rear brakes?

Why did you choose to retain the combo valve?

Good question. Why did I retain the OEM combo valve? Well, I was trying to keep as original as possible, but that idea was ditched out very quickly . I already replaced it with the Wilwood proportioning valve. So now there is no OEM combo valve. I am fine tuning the system. I think I may have locked the fronts yesterday during testing but I didn't have time to double check. I will try to test this weekend.

I also talked to Wilwood and one of the issues I may be running into is that the piston area of the rear brakes is slightly more than the front brakes. Still I think it should work, but I will need to do more testing. The rear brakes are adjusted by the parking brake so I can reduce the piston travel in the rear with tighter parking brake, but obviously, I can't be dragging the pads too tight.

 

[tony-muscle]

do the rotors have good cross hatching ?

Yes. The rotors have about 2,000 miles and they were Wilwood's.

 

[tony-muscle]

Some time ago I replaced the brakes at the four corners. In the front I installed Wilwood's 11.3" rotor kit with 4-piston calipers (140-13477). In the rear I installed a conversion kit that uses the ElDorado type of rear brake calipers. Recently, I replaced the master with a Wilwood tandem (260-8555) with a 1" bore. All the tubing and hoses are new. I also have a proportioning valve on the rear circuit. That said, everything has been replaced except the combination valve. However, I rebuilt the combination valve with the kit from Muscle Car Research and removed the integrated proportioning valve springs of the combination valve. My issue is that the car is not braking as I was hoping it would. With the proportioning valve all closed I am able to lock the rear brakes, but I have not been able to lock the front brakes. I expected that with the brake system that I have I should have been able to lock up the front brakes. I understand that I don't actually want to lock the front brakes for efficient braking, but the fact that I am not able to lock them when fully stepping on the pedal is telling me that something is not right. The only suspect I have now is the combination valve and I am wondering if I should eliminate it and go with a tee to the front. What else can be in the combination valve that could cause the front brakes to be inefficient or am I missing something? I guess that the only thing I will lose is the functionality of the idiot brake light.

You might want to try a power brake bleeder, like this. There website has a adaptor that seals to top master cyl. just pump up to 20 pounds and ALL bubbles are expelled, thats how o.e.m. are done today, works like a charm, regardless of loops in line, ect. 

I don't think they have an adapter for the Wilwood master I have.

 

[nailpounder]

see if this helpshttps://www.onallcylinders.com/2013/10/29/video-master-cylinder-bore-size-affects-braking/

Video How Master Cylinder Bore Size Affects Braking - OnAllCylinders.html

 

[nailpounder]

https://www.onallcylinders.com/2013/10/29/video-master-cylinder-bore-size-affects-braking/