Mustang 428 Cobra Jet Registry Forum

Discussion => Restoration Tips & Techniques => Topic started by: anghelrestorations on July 10, 2010, 01:12:25 pm

Title: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on July 10, 2010, 01:12:25 pm

Some pictures of the rebuild I just finished on this brake assembly done for a 69 Mach 1...with the correct plating on the mounting bracket.  The rebuild itself was not that difficult, but taking it apart takes patience since most of these have a good amount of corrosion.  First picture shows a comparison with what most of these look like that I have taken off cars.   

(http://i191.photobucket.com/albums/z213/azscj/P7100201.jpg)

(http://i191.photobucket.com/albums/z213/azscj/P7100210.jpg)

(http://i191.photobucket.com/albums/z213/azscj/P7100204.jpg)

Title: Re: Restored pressure differential valve and proportioning valve
Post by: Brian Conway on July 10, 2010, 03:36:29 pm
Nicely done.  Thanks for the pictures.  Brian
Title: Re: Restored pressure differential valve and proportioning valve
Post by: jonw29 on July 10, 2010, 04:01:36 pm
That's sexy.God job
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on July 12, 2010, 02:46:28 am

Adding a picture of this mounted in the car as well, with all the brake lines connected. 

(http://i191.photobucket.com/albums/z213/azscj/P7110221.jpg)
Title: Re: Restored pressure differential valve and proportioning valve
Post by: b--r30 on July 21, 2010, 10:32:11 am
Marcus,great job especially the yellow dichromate on the bracket.Seen a lot of eye-popping cars with cruddy brackets on their dist block.One thing,and I know you're gonna hate me,I think the 2 weld studs on the bracket were installed after the bracket was plated and were black oxide like the nuts.It's not my fault that I turned into a nit picker.It's the site.Got me running scared on every move on my car for fear of incorrectness.That being said,I don't see any way to get the studs out or back in without wrecking the bracket.
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on July 22, 2010, 12:01:08 am

Actually the two weld studs from what I see were dichromate as well.  I have one original unrestored crusty bracket/distribution block and you can see the dichromate finish on the threads themselves of those studs. 
So I would need to see an original assembly line untouched bracket to show that it was different....but everything I have points to that entire bracket being the same finish like in the photos. 
Title: Re: Restored pressure differential valve and proportioning valve
Post by: DragPack69 on July 24, 2010, 08:56:48 pm
Beautiful job Marcus, I understnd the plating process, can you shed a little knowledge on how you get the brass clean and looking like that?

John
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on July 25, 2010, 03:01:29 pm

John - for the brass you need to use a bead blasting cabinet with a light abrasive media.  Need to be careful not to hit the plated bracket, and then when finished a light hand polish to bring the natural brass finish back.  The main thing here is you do not want something that is too shiny and not something that looks like it was beadblasted.  It helps to have a few spare pieces to practice with until you get the right technique down. 
Title: Re: Restored pressure differential valve and proportioning valve
Post by: DragPack69 on July 25, 2010, 06:54:08 pm
Thanks Marcus, I`ll give it a try.

John
Title: Re: Restored pressure differential valve and proportioning valve
Post by: 69SCJQ4.30 on September 30, 2010, 12:36:33 am
I'm curious as to the adapter in the one master cyl. line? I have not seen that on any disc brake cars I have worked on before?

Bill
Title: Re: Restored pressure differential valve and proportioning valve
Post by: sah62 on September 30, 2010, 06:07:30 am
That's called an "impulse valve" in the master parts catalog. Marcus asked the same question a while back:

http://www.428cobrajet.org/forum/index.php?topic=15366.0

We didn't reach any conclusions.
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on October 01, 2010, 01:42:23 pm

Actually, I did reach a conclusion.  Refer to the link Scott posted above that I just updated. 
Title: Re: Restored pressure differential valve and proportioning valve
Post by: Brian Conway on October 30, 2010, 12:52:59 pm
Marcus; I can't get the piston to center under the sending unit.  I have tried bleeding  at front and rear cylinders, but, the light won't go off.  My question:  can the piston be moved forward or backwards simply by pushing? 
     1.  Bleed the fluid level down in the master cylinder to reduce spillage.
     2.  Remove the end plug/cap nearest the fire wall.
     3.  Remove the Horizontal left front brake line at forward, shock tower, area.
     4.  Insert prod to move piston enough to center under sending unit         

      Thanks,  Brian
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on October 31, 2010, 10:32:14 am

Brian,  I have never tried what your asking here....but in theory you could possibly be able to do this, unless the piston is centered on the wrong side then pushing would never work. 
Normally if I have this situation happen on a car I open up a wheel cylinder, or caliper, to create opposite pressure in the system to move the piston.  I assume you tried that?
Title: Re: Restored pressure differential valve and proportioning valve
Post by: redscj on October 31, 2010, 11:04:56 am
Quote
the light won't go off
     Frustrating problem. I think this is what Scott's handy dandy tool is for. Have you been able to get the light to turn off? I'm not exactly sure about the schematics but could there be a short or ground problem that keeps it on. Any chance that you can bleed the brakes with the key on to see if a helper can verify that the light turns off as the piston passes the center position. Good luck.
Title: Re: Restored pressure differential valve and proportioning valve
Post by: Brian Conway on October 31, 2010, 11:58:18 am
     Thanks for the replies.  My easy fix idea is moot anyway.  Neither fitting, the front left brake nor the plug on the other end of the dist. block, will budge.  Marcus when you say the other end do you mean towards the firewall? 
     A easy continuity test is to remove the sending unit from the dist. block, plug it back in, and move the plunger up and down.
 With the key in the ' ON ' position the ' BRAKE SYSTEM " light will flicker - or not.  Will try bleeding brakes again to see if it will center.  Thanks,  Brian
Title: Re: Restored pressure differential valve and proportioning valve
Post by: geraldt52 on October 31, 2010, 05:19:38 pm
Brian, it may require more pressure on the valve then you are thinking is required...they sometimes tend not to move when just a slight imbalance is introduced.  Open either the front or rear, then try stomping on the brake pedal, hard and quickly, to see if you can get the piston to move...if you have power brakes it will help to have the engine running.  It is indeed possible to sit in the car with the switch on and watch the light to determine when you've centered the valve.  I've had to move a few back and forth several times in order to finesse it into "center" where the light is out.  Once you've done this by yourself a few times, the $10 Scott wants for the little tool will seem like quite a bargain...although it's not going to do you any good where you're at right now.  
Title: Re: Restored pressure differential valve and proportioning valve
Post by: Craig429 on November 25, 2010, 08:35:21 pm
I have read that in 70 they went to a different style pressure differential valve with a built in proportioning valve.  Is there a change over date such that early 70's may have the 69 style as AZSCJ posted?  What is correct for my September 12 1969, Metuchen 1970 SCJ?
I have seen one that was like AZSCJ posted but claimed it was from a 70. 
Craig
Title: Re: Restored pressure differential valve and proportioning valve
Post by: Chris Teeling on November 26, 2010, 10:10:47 pm
I am taking a shot at restoring 3 distribution blocks and 4 differential pressure valves and have a few questions:

Marcus, did you remove the bracket from the distribution block for plating?

Does anyone have a proven tool / method that I could use to hold the differential pressure valve without damaging it while I break the brake line fitting loose from the round end?

Thanks in advance!
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on November 26, 2010, 11:21:08 pm

Chris - no, I did not remove the bracket but plated the whole assembly and then carefully removed the plating from the brass body.  It takes a decent amount of time...just need to be patient. 

As for removing the brake line from the valve, I used a thick rag and wrapped this around the valve in the exact same area where it would be covered by the bracket.  This way any scratches would be covered once the bracket is in place again.  To hold it in place I carefully used vise grips (with a round jaw, not the flat jaw vise grips).     
Title: Re: Restored pressure differential valve and proportioning valve
Post by: anghelrestorations on November 26, 2010, 11:27:41 pm
Craig - I cant see that any 70 Mustang would have the 69 style brake distribution valve installed.  Ford made plenty of changes from 69 to 70 and I have never seen an original car with a 69 style system, and think it would be incorrect if I did see it.  For your car I would use the 70 style to be correct.