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Braking issue?

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1986F150Six

Braking issue?

Administrator

This morning, I drove my son's 1984 F150 with power brakes. I drove it for several blocks having to brake several times. The brakes worked fine. I made a stop and when I restarted the engine, with my foot on the brake, it could be felt to modulate. I drove it home without any more problems.

When I got home, I opened the hood and checked the large hose providing vacuum to the brake booster. The hose looks okay and the clamps are in place. I did notice that the rubber grommet on the booster body seems quite loose when the elbow is manipulated. Can this be replaced? Can someone provide an engineering number for the grommet? Does one pull on the elbow while twisting back and forth in order to remove the elbow? Can a replacement elbow be obtained should the current one [original?] break?

Thanks!

Gary Lewis

Re: Braking issue?

Administrator

David - I'm not seeing any breakdown of the booster. It is just base part # 2005 and there don't seem to be any parts for it.

But it is normal for the brakes to change as you start the truck. In fact, if I remember right one of the tests is to put your foot on the brake, hard, and then start the engine. The pedal should go farther down if the booster is working.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

grumpin

Re: Braking issue?

In reply to this post by 1986F150Six

Here’s this on the power booster check valve, if that’s what you’re talking about. Not in stock though.

Edit: x2 what Gary said!

https://www.rockauto.com/en/catalog/ford,1984,f-150,4.9l+300cid+l6,1121432,brake+&+wheel+hub,power+brake+booster+check+valve,1876

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

Gary Lewis

Re: Braking issue?

Administrator

David - This will show up in your mailbox, although I'm not exactly sure when. That's because I don't know if I'll be able to make it to the shipping spot tomorrow, and if if I do whether or not it'll go out. We have a major winter storm hitting soon.

)

Gary, AKA "Gary fellow": Profile

Ford F834

Re: Braking issue?

Administrator

This post was updated on .

In reply to this post by 1986F150Six

Hi David! I agree that some pedal modulation is normal, but if it feels like a lot, or it is a new behavior out of the system I would (also) inspect the hose connections to the vacuum reservoir(s) and test the integrity of the coffee can reservoir if so equipped.

SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD

STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering

BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2

mat in tn

Re: Braking issue?

I always thought it was a juice can. Who knew?

1986F150Six

Re: Braking issue?

Administrator

Thanks to all who have replied. I would have responded sooner, but have been experiencing total loss of Internet service and have had 3 service calls by AT&T and a couple of phone calls originating in other parts of the world.

Gary, I hope that you and Janey are okay and can stay warm. Thank you so much for the part!

Jonathan, the very quick pulsating upon start-up is new. I will check all vacuum line connections.

Dane, thank you for the link to RockAuto for the check valve.

Mat in tn, thanks for your interest.

Gary Lewis

Re: Braking issue?

Administrator

David - I hope you and Natalie keep warm as well. The storm seems to have fizzled here, although they are still saying there's more to come.

And I hope your internet is back. I'd be lost w/o that.

Gary, AKA "Gary fellow": Profile

Ford F834

Re: Braking issue?

Administrator

In reply to this post by mat in tn

mat in tn wrote

I always thought it was a juice can. Who knew?

Maybe it was just the Lariat trim and diesels that got the coffee can… all the others were pineapple juice 😅

1986F150Six

Re: Braking issue?

Administrator

The parts arrived yesterday, Gary. I will plan to install them tomorrow.

My son and I thank you for your generosity!

Gary Lewis

Re: Braking issue?

Administrator

Welcome, David and Daniel.

Gary, AKA "Gary fellow": Profile

Machspeed

Re: Braking issue?

Administrator

In reply to this post by 1986F150Six

I hope that works out for you, Dave. When mine did that, I had to replace the booster.

John

"Blackie" - 1986 F150 4x4 - Mildly warmed over 351W HO - Original owner

FuzzFace2

Re: Braking issue?

FYI you can get that check valve & the rubber at most parts stores in the help area as it was a common part back in the day on the hooks.

I would also replace the rubber hose just make sure it is rated for vacuum as gas hose may get sucked closed and no vacuum would get to the booster.
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

1986F150Six

Re: Braking issue?

Administrator

The rubber grommet removed has a small tear on the I.D. sealing surface. The substitution of the grommet only [for testing purposes] has been completed and the truck will soon be driven as my son has errands and will provide feedback.

1986F150Six

Re: Braking issue?

Administrator

Well, the occasional pulsating/modulating brake pedal is still alive. Next, the check valve will be replaced.

mat in tn

Re: Braking issue?

pulsating is an odd symptom description. it always leads me to warped rotors. does it move as you start it once or does it "pulse" as you hold your foot on the pedal?

1986F150Six

Re: Braking issue?

Administrator

mat in tn wrote

pulsating is an odd symptom description. it always leads me to warped rotors. does it move as you start it once or does it "pulse" as you hold your foot on the pedal?

My description lacked clarity... the rapid pulsating feeling comes through the brake pedal as the brakes are being released, not before or during brake application. It reminds one of the feeling of antilock brakes when the road is icy.

mat in tn

Re: Braking issue?

does it make any noise? pulsing while letting off the brakes is even stranger. any chance that the bushing is missing between the brake lever pin and the power booster arm loop right above the brake pedal causing a mechanical "chatter". I had an instance years ago where my 86 had a booster going bad due to rust and it was caused by water getting between the booster and firewall and the plastic cover collected it and soaked the cotton packing material. eventually it rusted bad enough to start getting rough to move and stepping on the pedal was no different but letting off felt like a washboard. until then I did not know I had an issue. also, without the radio on I could hear the air leak when letting off.

1986F150Six

Re: Braking issue?

Administrator

mat in tn wrote

does it make any noise? pulsing while letting off the brakes is even stranger. any chance that the bushing is missing between the brake lever pin and the power booster arm loop right above the brake pedal causing a mechanical "chatter".

No noise. Yesterday, the original check valve was removed and compared to the replacement provided by Gary. When blowing into the replacement valve's smaller port [engine side], the check valve prevented flow. The original one had no resistance to the same blowing.

As of last night, the rapid pulsating has not happened since the replacement of the check valve. Time will tell, but I am optimistic that the problem has been solved.

Gary Lewis

Re: Braking issue?

Administrator

Glad to see that, David.

Gary, AKA "Gary fellow": Profile